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Design, Synthesis and Characterization of Novel Tetrahydropyran-based Bacterial Topoisomerase Inhibitors with Potent Anti-Gram Positive Activity. Jean-Philippe Surivet, Cornelia Zumbrunn, Georg Rueedi, Christian Hubschwerlen, Daniel Bur, Thierry Bruyère, Hans Locher, Daniel Ritz, Wolfgang Keck, Peter Seiler, Christopher Kohl, Jean-Christophe Gauvin, Azely Mirre, Verena Kaegi, Marina Dos Santos, Mika Gaertner, Jonathan Delers, Michel Enderlin-Paput, and Maria Boehme J. Med. Chem., Just Accepted Manuscript • DOI: 10.1021/jm400963y • Publication Date (Web): 22 Aug 2013 Downloaded from http://pubs.acs.org on August 23, 2013
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Journal of Medicinal Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
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Design, Synthesis and Characterization of Novel Tetrahydropyran-based Bacterial Topoisomerase Inhibitors with Potent Anti-Gram Positive Activity. Authors: Jean-Philippe Surivet,* Cornelia Zumbrunn, Georg Rueedi, Christian Hubschwerlen,+ Daniel Bur, Thierry Bruyère, Hans Locher, Daniel Ritz, Wolfgang Keck,+ Peter Seiler, Christopher Kohl, Jean-Christophe Gauvin, Azely Mirre, Verena Kaegi, Marina Dos Santos, Mika Gaertner, Jonathan Delers, Michel Enderlin-Paput, Maria Boehme. Actelion Pharmaceuticals Ltd, Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
ABSTRACT There is an urgent need for new antibacterial drugs that are effective against infections caused by multi-drug resistant pathogens. Novel non-fluoroquinolone inhibitors of bacterial type II topoisomerases (DNA gyrase and topoisomerase IV) have the potential to become such drugs as they display potent antibacterial activity and exhibit no target-mediated cross-resistance with fluoroquinolones. Bacterial topoisomerase inhibitors that are built on a tetrahydropyran ring linked to a bicyclic aromatic moiety through a syn-diol linker, show potent anti Gram-positive activity, covering isolates with clinically relevant resistance phenotypes. For instance, analog 49c was found to be a dual DNA gyrase-topoisomerase IV inhibitor, with broad antibacterial activity and low propensity for spontaneous resistance development, but suffered from high hERG K+ channel block. On the other hand, analog 49e displayed lower hERG K+ channel block, while retaining potent in vitro antibacterial activity and acceptable frequency for resistance development. Furthermore, analog 49e showed moderate clearance in rat and promising in vivo efficacy against Staphylococcus aureus in a murine infection model.
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INTRODUCTION The selective pressure exerted by the use of antibiotics has inevitably resulted in the dissemination of drug resistant bacteria, among which the ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species)1 are of utmost concern. These pathogens cause not only the major part of hospital-acquired infections (leading to a death toll of approximately 100,000/year in the US) but also constitute a financial burden to healthcare systems all over the world2-4. The development of novel small molecule antibacterial drugs is therefore urgently needed. At the dawn of the 21st century, it was common belief that genomic and associated new technologies would deliver a plethora of new antibacterial drug targets5,6 and thus new chemical entities lacking cross-resistance with clinically used antibacterial drugs. Unfortunately, the efforts have not yet borne fruit and a significant research effort is still dedicated to the ‘old’ but clinically validated targets7 to fill the antibiotic pipeline8. Bacterial type II topoisomerases (DNA gyrase and topoisomerase IV (Topo IV)) are heterotetramers of GyrA2GyrB2 and ParC2ParE2 (E. coli) or GrlA2GrlB2 (S. aureus) respectively. They have been validated as targets for antibacterial therapy ever since it was recognized that the fluoroquinolone class of drugs can inhibit the topoisomerase function. The antibacterial spectrum of activity was expanded from nalidixic acid to newest fluoroquinolones9, but cross-resistance still emerged. Among several resistance mechanisms10, single amino acid changes in the quinolone resistance-determining region (QRDR) of GyrA (Ser84Trp) or GrlA (Ser80Phe)11,12 of S. aureus reduces dramatically fluoroquinolones affinity binding and therefore their inhibitory effect13,14. However, a new avenue was opened in the field of bacterial topoisomerase inhibition when researchers at GlaxoSmithKline (GSK) and Aventis independently disclosed closely related novel non-fluoroquinolone based topoisomerase inhibitors (so called NBTIs)15,16, devoid of cross resistance with fluoroquinolones. The Aventis program, which was continued at Novexel, capitalized on the initial hit scaffold and its attractive properties, leading to 1 (NXL-101)17 (Figure 1). Unfortunately, its development had to be discontinued after detection of unacceptable QT interval prolongation18. The GSK program took a different direction resulting in successive generations of NBTIs 219, 320 and 621 and could even profit at a later
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stage from the resolution of the X-ray structure of 4 (Figure 1) bound to DNA and S. aureus DNA gyrase22. The crystallographic studies provided the basis to rationalize the lack of cross resistance between NBTIs and fluoroquinolones and also led to the design of novel inhibitors (Figure 1). Recently, a publication by AstraZeneca showed that 2 and 3 block the hERG K+ channel significantly (IC50256
>256
0.5
Compounds 1, 2, 5 and 6 were prepared in our laboratories as reported in literature. bIsolated from Staphylococcus aureus ATCC 29213.
Isolated from Escherichia coli ATCC 25922. dQuinolone-resistant (QR) enzyme containing a S84L mutation isolated from
Staphylococcus aureus A-798. eEnzyme containing the D83N mutation isolated from a laboratory strain resistant to 1. fCiprofloxacin, commercially available.
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Table 2: Antibacterial activities of compounds 1, 2, 5 and 6 (MIC in mg/L)28 S. aureus
S. aureus
S. aureus
E. faecium
S. pneumoniae.
E. coli
P. aeruginosa
wta
MRSA, QRb
D83Nc
QRd
wte
wtf
wtg
1
0.125
0.25
>8
1
1
>8
>8
2
0.015
0.015
0.25
0.063
0.063
0.25
8
5
0.015
0.015
1
0.5
0.25
8
>8
6
0.015
0.015
1
0.06
0.015
1
>8
CIPh
0.25
>8
0.25
>8
1
0.016
0.25
Compds
a
Staphylococcus aureus ATCC 29213. bStaphylococcus aureus A-798. cLaboratory strain. dEnterococcus faecium A-949 vancomycin-
resistant. eStreptococcus pneumoniae ATCC 49619. fEscherichia coli ATCC 25922. gPseudomonas aeruginosa ATCC 27853. h
Ciprofloxacin (fluoroquinolone).
At the start of our investigations, no crystallographic data for GyrA complexed to a NBTI was available to support rational drug design of dual GyrA/ParC inhibitors. Enzymatic data recorded for compound 2, showed cross-resistance with 1, suggesting that both entities share a common binding site in the proximity of Asp83. NBTIs chemical structure can be divided in three parts: a methoxy substituted bicyclic aromatic left-hand side (LHS), a mono- or bicyclic lipophilic right-hand side (RHS) and a variable linker joining the two units. Superposition of compounds 1 and 2 (Figure 2) displayed a good overlay for LHS and RHS thereby defining the length of the linker as well as directionalities of the respective exit vectors. The linker, which can itself be divided in three parts (i.e. a central ring spacer and two flanked connecting units reaching the LHS and RHS respectively), differs significantly in compounds 1 and 2, sharing only a saturated 1,4-disubstituted six-membered ring as common motif. The amide functionality in 2 is co-planar with its LHS, leading to a straighter linker if compared with the hydroxy-propylidene (-CHOH-(CH2)2-) functionality in 1. Both inhibitors comprise a basic nitrogen in close vicinity to the RHS.
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Figure 2: a. Modeled superimposition of inhibitors 1 (blue bonds) and 2 (green bonds). Red: oxygen atoms; blue: nitrogen atoms; white: carbon atoms; yellow: sulfur atoms; green: fluorine atoms. The more balanced GyrA/ParC activity of 2 led us to design NBTIs containing a trans-3,6-disubtituted tetrahydropyran (THP) ring and a two atom (-A-B-) unit to connect this ring to the LHS (Scheme 1). We hypothesized that such a linker should be suitable to establish geometrically restricted compounds with favorable physicochemical and pharmacological profiles. Therefore, benzylic alcohols or diols, respectively (-A-B- = -CHOH-CH2- or -CHOH-CHOH-), were assumed to produce superior aqueous solubility if compared to amide (-A-B- = -HN-CO-) or ether (-A-B- = -O-CH2-) units. As side products on the way to the desired diol compounds, the (E)-alkene (-A-B- = -CH=CH-) and its saturated analog (-A-B- = -CH2-CH2-) could be obtained. As we could not predict the effect of the THP-ring stereochemistry, we decided to explore both enantiomeric series. In case the –A-B- motif is a diol, we have chosen to limit our investigations to syn-diols for synthetic reasons. Finally, known RHS-units were connected to the THP-core through the aminomethyl side chain. CHEMISTRY As illustrated in Scheme 1, the exploration of the SAR of the newly designed topoisomerase inhibitors was facilitated by using a modular synthetic approach based on the following three key building blocks: i) a bicyclic aromatic LHS, ii) a central THP core, and iii) a bicyclic aromatic RHS. The
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impact of the stereochemistry of the central THP core can be rapidly explored by using building blocks 7 and its enantiomer ent-7. Scheme 1
In contrast to the well-documented synthesis of the alcohol (3R,6S)-7 from tri-O-Ac-D-glucal29, the synthetic access to the enantiomer (3S,6R)-ent-7 had to be developed first. According to Scheme 2, the known ω-alkenoate 830 was reduced to the corresponding alcohol with lithium borohydride in tetrahydrofuran, and a treatment with meta-chloroperbenzoic acid under buffered conditions yielded epoxide 9 as an equimolar mixture of diastereomers. The following acid-promoted cyclization, using (+/-)-10-camphorsulfonic acid (CSA), afforded a separable mixture of enantiopure ent-7 (arising from of the specific attack of the alcohol on the (S)-configurated epoxide) and the pyrrolidine derivative 10 (resulting from the cyclization of –NH-tert-butoxycarbonyl on the (R)-configurated epoxide).
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Scheme 2a
According to Scheme 1, the introduction of the A-B linker required the preparation of appropriately substituted central building blocks featuring a proper reaction handle FG2. The following modifications of alcohol (3R,6S)-7 leading to central building blocks 12, 15 and 18 are summarized in Scheme 3. Amide 12 was obtained in two steps starting with the oxidation of alcohol 7 to acid 11 by sodium periodate in presence of a catalytic amount of ruthenium trichloride29. A subsequent treatment of the acid 11 with N-hydroxysuccinimide (NHS) and N,N-dicyclohexylcarbodiimide provided its activated form which upon treatment with gaseous ammonia yielded the targeted amide 12, with no loss of stereochemical information31 (Scheme 3). Scheme 3a
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The oxidation of alcohol 7 using pyridine-sulfur trioxide complex (py.SO3) and dimethylsulfoxide32 in dichloromethane afforded aldehyde 13. The Wittig olefination33 leading to alkene 14 was performed by the reaction of methylenetriphenylphosphorane (generated from methyltriphenylphosphonium bromide and potassium tert-butoxide) with aldehyde 13. The hydroboration of alkene 14 with 9borabicyclo[3.3.1]nonane in tetrahydrofuran led after oxidative work-up to the intermediate primary alcohol34 that was further oxidized to aldehyde 15 using Dess-Martin periodinane35 (Scheme 3). As observed in the case of amide 12, it is noteworthy to state that no epimerization occurred by passing from alcohol 7 to homologated aldehyde 15. Phenyltetrazole sulfone 18 was obtained by oxidation of sulfide 17 with hydrogen peroxide in presence of ammonium molybdate. The formation of 17 was initially achieved by direct coupling of alcohol 7 with phenyltetrazole thiol (PT-SH) under Mitsunobutype conditions (combining triphenylphosphine (PPh3) and diisopropyl azodicarboxylate (DIAD))36. However, nucleophilic substitution of iodide 16 with PT-SH in presence of potassium hydroxide in refluxing ethanol turned to be more effective. The intermediate iodide 16 was obtained through tosylation followed by displacement with sodium iodide in refluxing acetone (Scheme 3). The bromides 19a and 22a-25a (R2 = Br) were prepared by refluxing the corresponding hydroxyl derivatives (R2 = OH)37 in neat phosphorous tribromide. As illustrated in Scheme 4, the preparation of aldehydes 19b-22b consisted in trapping a lithio anion that was generated either from bromides 19a or 22a (treatment with n-butyl lithium or lithium diisopropylamide at -78°C), or by fluorine-directed ortho-lithiation of compounds 20a or 21a with dimethylformamide. Dechlorination of aldehyde 21c was done by hydrogenolysis using palladium on carbon and triethylamine under hydrogen atmosphere to yield aldehyde 21b. The syntheses of aldehydes 23b-26b started from bromides 23a-25a (R2 = Br) or triflate 26a (R2 = OTf)38 via Suzuki coupling39 with trans-phenylvinyl boronic acid giving rise to the respective phenyl alkenes 23c-26c which were converted to the corresponding intermediate diols 23d26d. The desired aldehydes 23b-26b were then subsequently formed under standard periodic cleavage conditions. On the other hand, aldehyde 27b was obtained by hydrolysis of dibromide 27c obtained from methyl quinoxaline 27a37 by treatment with an excess of N-bromosuccinimide in presence of azobisisobutyronitrile (Scheme 4).
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Scheme 4a
According to Scheme 5, the general synthetic access to final NBTI described herein involved the coupling of the central THP core to the bicyclic aromatic LHS, followed by a reductive amination using readily accessible RHS aldehydes. The ether linkage of derivative 28a was constructed using a Mitsunobu coupling reaction (DIAD, PPh3) between alcohol 7 and hydroxy-naphthyridine 23e26. In contrast, amide 12 was coupled to bromide 23a via a Buchwald-type reaction40 to form the amidecontaining derivative 29a. Treatment of bromide 23a with n-butyl lithium at -78°C generated the lithio anion that reacted with aldehyde 15 to yield benzylic alcohol 30a as an equimolar mixture of diastereomers41. Julia-Kocieński coupling42 of PT-sulfone 18 and aldehyde 23b using potassium bis(trimethylsilyl)amide as a base provided (E)-alkene 31a which was hydrogenated over palladium on carbon to afford the corresponding saturated derivative 34a. On the other hand, Sharpless asymmetric dihydroxylation43 of alkene 31a gave rise to syn-diols with an excellent diastereoselectivity (>95%)41. The use of commercial AD-mix-α or AD-mix-β gave access to both diastereomeric series as demonstrated with the formation of intermediates (1S,2R)-35a and (1R,2S)-36a. The corresponding free amines 28b-31b and 34b-36b were obtained by treatment with trifluoroacetic acid (TFA), either neat or diluted in dichloromethane. From these amines, variable RHS moieties were introduced via reductive amination reaction44 with aldehydes 3245 or 3346, giving rise to NBTIs 28c-31c, 28d-31d,
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34c-36c, 34d and 35d. A set of THP-based topoisomerase inhibitors belonging to the enantiomeric series could be prepared by the same synthetic pathway but using sulfone ent-10 as a partner in the Julia-Kocieński coupling. Likewise, asymmetric dihydroxylation of ent-31a using either AD-mix-α or -β proceeded smoothly to afford the corresponding syn-diols ent-35c and ent-36c (Scheme 5). Scheme 5a
The Julia-Kocieński coupling of aldehydes 19b-22b, 24b-27b and sulfone 18 provided (E)-alkenes 3744 with (E)/(Z)-selectivities bigger than 6/141. The (1R,2S)-syn-diols 45a-52a were prepared by using AD-mix-β as dihydroxylating reagent. After removal of the tert-butoxycarbonyl (Boc) group with TFA, the resulting amines 45b-52b were transformed to NBTIs 45c-52c using aldehyde 32 in the reductive amination reaction. Finally, the intermediate amines 48b and 49b were coupled under reductive amination conditions with aldehydes 33, 5347, 5448 and 5549 to access NBTIs 48d-f and 49dg (Scheme 6).
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Scheme 6 a
RESULTS AND DISCUSSION The antibacterial activity, expressed as MIC (minimal inhibitory concentration, [mg/L]) of the novel chemical entities, was measured against a panel of bacterial strains including Staphylococcus aureus (S. aureus), Streptococcus pneumoniae (S. pneumoniae), Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) ATCC strains as well as a S. aureus D83N DNA gyrase mutant strain, resistant to NBTIs such as 1. All the novel chemical entities were also evaluated for inhibition of DNA gyrase and topo IV isolated from wild type S. aureus and E. coli and for block of hERG K+ channels. As shown in Table 3, all molecules based on a 6-methoxy-1,5-naphthyridine scaffold showed potent binding to S. aureus DNA gyrase and E. coli Topo IV, with IC50 in the nanomolar range for the best compounds such as 30, 34 and 35. The ether linker present in 28c-d led to lower enzyme potency, and accordingly, weaker antibacterial activities. The two amide derivatives 29c-d displayed much weaker antibacterial activities compared to the related GSK inhibitor 2. However, precipitation of 29c due to low solubility prevented reliable inhibition measurements. The most potent antibacterial activities
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were measured for derivatives containing an ethylene, a hydroxy- or a 1,2-dihydroxy-ethylene unit (30c-d, 34c-d and 35c-d respectively) whereas alkenes 31c,d showed higher MICs. Compounds comprising a pyridothiazinone moiety as RHS displayed consistently superior target potency compared to molecules containing the dioxinopyridine moiety, which translated into lower MICs and a broader antibacterial spectrum, as exemplified by compounds 30c and 30d. While both molecules displayed good antibacterial activities on S. aureus, 30c showed a 4-fold lower MIC on wild type S. pneumoniae (0.03 mg/L), and at least a 8-fold lowered MIC on E. coli (1 mg/L) when compared to 30d. The same trend was observed for 34c and 34d as well as for 35c and 35d. The lack of antibacterial activity of compounds 28d-35d against wild-type E. coli was not further investigated, but may result from a combination of reduced enzyme potency on target and lower cytoplasmic accumulation in E. coli compared to the related derivatives having a pyridothiazinone RHS (28c-36c). Moreover, the pyridothiazinone inhibitors exhibit good target potency against S. aureus Topo IV and E. coli DNA gyrase respectively, whereas inhibitors comprising a dioxinopyridine failed to do so. Similar to inhibitor 2, the most potent dual S. aureus DNA gyrase-Topo IV inhibitors (34c and 35c) displayed antibacterial activities against the S. aureus D83N mutant (MIC range 0.5-1 mg/L). In general, as shown in Table 3, a high level of hERG K+ channel block was measured for this set of compounds with the exception of compound 35d, suggesting that designing compounds with high antibacterial activity and low hERG K+ channel block should be possible.
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Table 3: SAR of two-atom linker A-B
Cpds
RHS
Linker
MIC (mg/L)
Gyrase
Topo IV
hERG
SCIA (IC50)
RIA (IC50)
blocke
S. a.a
S. a.R b
S. p.c
E. c.d
S. a.
E. c.
S. a.
E. c.
28c
1
0.5
4
0.25
4
0.125
2
8
0.125
70
28d
2
2
>8
4
>8
0.5
>8
>8
0.5
19
29cf
1
0.25
>8
0.5
>8
0.125
0.5
2
0.125
99
29d
2
0.125
>8
0.25
>8
0.125
>8
>8
0.125
71
30c
1
0.03
0.5
0.03
1
8
8
0.125
>8
0.125
>8
>8
0.125
66
31c
1
0.125
4
1
4
0.125
0.5
2
0.03
94
31d
2
0.25
>8
1
>8
0.125
>8
>8
0.125
88
34c
1
0.03
1
0.06
1
0.03
0.12
0.5
0.03
97
34d
2
0.06
4
0.5
8
8
0.125
82
35c
1
0.03
0.5
0.06
1
8 mg/L on Pseudomonas aeruginosa ATCC 27853.
Lead Optimization The absolute stereochemistry of the syn-diol linker modulated the antibacterial activity to a significant extent (Table 4). While inhibitors 35c and ent-36c featuring a (1S,2R)-configurated dihydroxyethylene linker displayed low MICs against Gram-positive S. aureus and S. pneumoniae (0.03 to 0.06 mg/L) and Gram-negative E. coli (1-2 mg/L), the MICs recorded for their respective (1R,2S)-
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configurated diastereomers 36c and ent-35c, were more than 10-fold higher against those pathogens. These observations were in agreement with the lower DNA topoisomerases inhibitory activities recorded for 36c and ent-35c in comparison to those of 35c and ent-36c and 52c respectively. Interestingly, the (3R,6S)- or (3S,6R)- configuration of the THP core (referring to the progenitor building blocks 7 and ent-7) had no influence on antibacterial potency. All diastereomers or enantiomers of 35c that were evaluated for hERG K+ channel block, exerted higher affinity for this channel if compared to 35c and no clear trend could be observed with respect of the different stereochemistries. Table 4: Influence of the stereochemistry of the 1,2-dihydroxy-ethylene linker and the THP ring
Cpds
MIC (mg/L)
Gyrase
Topo IV
hERG
SCIA (IC50)
RIA (IC50)
blocke
S. a.a
S. a.R b
S. p.c
E. c.d
S. a.
E. c.
S. a.
E. c.
35c
0.03
0.5
0.06
1
0.03
0.5
0.5
0.125
36
ent-35c
0.5
>8
0.5
4
0.125
8
>8
0.125
45
36c
1
>8
1
>8
0.5
8
>8
0.125
93
ent-36c
0.03
0.5
0.03
1
0.03
0.5
8
0.125
70
a
Staphylococcus aureus ATCC 29213. bStaphylococcus aureus A-234 gyrA: D83N. cStreptococcus pneumoniae ATCC 49619. dEscherichia
coli ATCC 25922, e% block of hERG K+ channel measured at 10 µM. All compounds showed MIC >8 mg/L on Pseudomonas aeruginosa ATCC 27853.
As the stereochemistry of the central THP-core had no influence on antibacterial potency, we chose to pursue our investigations on the series stemming from the more readily available alcohol 7 and several analogs of 35c featuring various bicyclic aromatic LHS moieties, were evaluated. As shown in Table
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5, its 6-methoxyquinoline analog 51c was less active. The nitrogen atom at the generic position noted U contributes to an enhanced antibacterial potency. This was confirmed by comparing 47c with 49c and 46c with 52c, respectively. Indeed, derivatives 45c, 48c, 49c and 52c, wherein U = N, shared a similar antibacterial profile, with good MICs against wild-type S. aureus and S. pneumoniae. As previously observed, these dual inhibitors of S. aureus and E. coli type II topoisomerases, exhibited antibacterial activity against D83N S. aureus mutant and wild type E. coli. In contrast, the nature of the groups in generic positions V, W and X (N, CH or CF) did not modulate potency to a significant extent. In general, derivatives 46c, 47c, 50c and 51c, wherein U = CH did not exhibit a dual target inhibitor profile and lacked antibacterial activity against D83N S. aureus mutant. Nonetheless, less block of the hERG K+ channel was observed for derivatives with U = CH. For compounds with U = N, slight differences were observed with respect to hERG K+ channel block, with IC50s in the 10µM range in case of X = CF (48c and 49c), whereas analogs for which X = CH (35c and 52c) showed slightly more potent hERG K+ channel block.
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Table 5: SAR of Left Hand Sides
Cpds
LHS
MIC (mg/L)
Gyrase
Topo IV
hERG
SCIA (IC50)
RIA (IC50)
blocke
S. a.a
S.a.R b
S. p.c
E. c.d
S. a.
E. c.
S. a.
S. a.
35c
0.03
0.5
0.06
1
0.03
0.5
0.5
0.125
70
45c
0.03
0.25
0.06
2
0.03
0.125
0.5
0.125
72
46c
0.25
>8
0.25
8
0.125
2
0.5
0.125
17
47c
0.25
>8
0.25
4
0.125
2
8
0.125
15
48c
0.06
1
0.5
4
0.03
0.5
2
0.125
44
49c
0.03
0.25
0.06
1
0.03
0.5
0.5
0.03
54
50c
0.03
4
0.25
4
0.125
2
8
0.125
20
51c
0.25
>8
0.25
4
0.25
2
8
0.125
24
52c
0.03
0.5
0.06
2
0.03
0.5
2
0.125
55
a
Staphylococcus aureus ATCC 29213. bStaphylococcus aureus A-234 gyrA: D83N. cStreptococcus pneumoniae ATCC 49619.
d
Escherichia coli ATCC 25922, e% block of hERG K+ channel measured at 10 µM.. All compounds showed MIC >8 mg/L on
Pseudomonas aeruginosa ATCC 27853.
From the latter observations, the influence of the RHS-moiety on hERG K+ channel block was established based on the 3-fluoronaphthyridine and 6-fluoroquinoxaline scaffolds (Table 6). Whereas both compounds 48c and 49c blocked hERG K+ channel in the low micromolar range, significantly reduced block was observed for the inhibitors 48d, 48f, 49d and 49g containing either a dioxinopyridine, a dioxinopyridazine, an oxathiinopyridine or an oxathiinopyridazine moiety. However, reduced hERG K+ channel block tracked in parallel with lower topoisomerase inhibition.
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For instance, compounds 48d, 48f, 49f and 49g, featuring a dioxinopyridine or a pyridazine-based moiety, still displayed potent inhibition of S. aureus DNA gyrase, but weak S. aureus Topo IV activity, thus resulting in limited antibacterial activity on the S. aureus D83N mutant strain (MIC 8mg/L or higher). The exchange of dioxino ring for a oxathiino ring resulted still a low S. aureus Topo IV activity but to an increased potency against S. aureus DNA gyrase. A good compromise between antibacterial activity and block of hERG K+ channel could be obtained for compound 49e. Structural analysis of diol 49e With the X-ray structure of compound 4 in complex with S. aureus DNA gyrase and a 20-bp DNA duplex in hand22, inhibitor 49e was docked into the active site of the protein-DNA complex in order to rationalize the proposed SAR (Figure 3). The 6-methoxy-1,5-naphthyridine moiety of 49e sits between two stretched DNA base pairs. Saturated linkers (ethylene, hydroxyl- or 1,2-dihydroxy-ethylene) allowed an unstrained fit of compounds as observed for 4, whereas amides, ethers and alkenes diverged from a linker path as defined by 4, ultimately leading to a suboptimal positioning of a (charged) H-bond donor that can interact with Asp83. Furthermore, the two hydroxyl units of 49e appear to be in a position to establish H-bonds with neighboring base pairs. The RHS of 49e resides in a hydrophobic pocket at the interface of the two GyrA subunits. The oxathiolopyridine ring of compound 4 and similarly the hydrophobic RHS of 49e establish van der Waals interactions with the surrounding hydrophobic residues, thereby featuring interactions between the sulfur atoms of the inhibitors and methionine side chains of GyrA.
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Figure 3. Docking pose of compounds 49e (yellow) superimposed on original inhibitor 4 (pink) in GyrB27-A56 complex X-ray (PDB-code: 2XCS). DNA is shown in green, while gyrase C-alpha backbone is blue.
Table 6: Novel bacterial topoisomerase inhibitors with reduced hERG K+ channel block
O
N
F
O
N
Cpds
LHS
Y
Z
S. a.R b
Y
O Z
OH
MIC (mg/L) S. a.a
N
LHS
N LHS2
N LHS1
OH O
F
H N
S. p.c
E. c.d
Gyrase
Topo IV
hERG
SCIA (IC50)
RIA (IC50)
blocke
S. a.
E. c.
S. a.
S. a.
48d
1
CH
O
≤0.015
8
0.125
8
0.125
8
8
0.5
11
48e
1
CH
S
≤0.015
2
0.03
8
0.03
8
8
0.125
33
48f
1
N
S
≤0.015
8
0.125
>8
0.125
8
>8
2
0
49d
2
CH
O
0.03
2
0.03
>8
0.03
8
8
0.125
10
49e
2
CH
S
≤0.015
2
≤0.015
8
0.03
8
8
0.125
19
49f
2
N
S
≤0.015
8
0.06
>8
0.125
8
8
0.5
3
49g
2
N
O
0.125
>8
0.5
>8
0.125
>8
>8
2
7
a
Staphylococcus aureus ATCC 29213. bStaphylococcus aureus A-234 gyrA: D83N. cStreptococcus pneumoniae ATCC 49619. dEscherichia
coli ATCC 25922. e% block of hERG K+ channel measured at 10 µM. All compounds showed MIC >8 mg/L on Pseudomonas aeruginosa ATCC 27853.
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Antibacterial profile of NBTI 49e As shown in Table 7, compound 49e was highly active against all S. aureus isolates tested including MRSA and fluoroquinolone-resistant strains (MIC90, 0.03 mg/L)50. In addition it showed good activity against other clinically relevant Gram-positive bacteria including S. pneumoniae and E. faecium VRE with MIC90s of ≤ 1 mg/L. Significant activity was also observed against Moraxella catarrhalis and Haemophilus influenzae. However, only weak or no activity was detected against other Gram-negative bacteria such as Escherichia coli or Pseudomonas aeruginosa. In summary, compound 49e has an antibacterial spectrum suitable for the treatment of Gram-positive and respiratory tract infections. Table 7. Antibacterial activities of 49e against clinical isolates (in mg/L) Nb of Organisms
MIC50
MIC90
Range
strains Staphylococcus aureus
35
≤ 0.015
0.03
≤ 0.015-0.06
MRSA subset
25
≤ 0.015
0.03
≤ 0.015-0.03
Staphylococcus epidermidis
16
0.06
0.25
0.03-0.25
Enterococcus faecalis
20
0.5
0.5
0.06-1
Enterococcus faecium VRE
20
0.25
1
0.03-4
Streptocococcus pneumoniae
24
0.06
0.125
0.03-0.25
Streptococcus pyogenes
14
0.03
0.06
0.015-0.125
Streptococcus agalactiae
13
0.25
0.5
0.125-0.5
Haemophilus influenzae
11
0.5
4
0.25-8
Moraxella catarrhalis
11
0.03
0.125
≤0.015-125
Spontaneous resistance frequencies of selected compounds were measured in S. aureus. Both 49c and 49e that displayed dual target activity (gyrase and Topo IV) showed 10 to 100-fold lower resistance frequencies compared to compound 1 targeting only gyrase (Table 8). This finding confirmed our working hypothesis that emergence of resistance should be slower with inhibitors acting on both targets.
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Table 8. Frequencies of spontaneous resistance development in S. aureus ATCC 25923 Resistance frequency at 4x the MIC at 16x the MIC 2.7 x 10-6 2.1 x 10-7
Cpds 1a
a
49c
8.8 x 10-8
1250
347
2.43
49e
291
344
30
1.20
52c
39
92
45
0.57
Assayed at 1µM compound concentration.
Compounds 34c and 52c, both featuring a pyridothiazinone RHS, showed a high in vivo clearance in the rat, whereas 49e with an oxathiinopyridine RHS, was cleared much more slowly and displayed significant bioavailability (F = 41%). Rat clearance measured for compounds 34c, 49e and 52c (Table 10) only partially matched the corresponding in vitro microsomal stability data in line with the notion that in vitro CLint is by and large an unbound parameter not confounded by plasma protein binding. Not surprisingly, the in vivo clearance of 49e and 52c reflects the in vitro metabolic stability once corrected for the fraction unbound in plasma (unbound clearance, CLu)51.
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Table 10: Pharmacokinetic parameters in rata CLa,b Cpds
fu
c
(mL/min//kg)
a
CLud
Vsse
t1/2f
AUCg (iv)
AUC (po)
Fh
(mL/min/kg)
(L/kg)
(h)
(ng*h/mL)
(ng*h/mL)
(%)
34c
36
ndi
nd
3.2
1.2
463
1320
29
49e
8.7
0.017
512
1
3
959
776
41
52c
53
0.18
294
18
5.9
313
817
26
Pharmacokinetic parameters following iv bolus injection of a 1 mg/kg dose (compounds 34c and 52c) or 0.5 mg/kg dose (compound
49e). bClearance. cFraction unbound in plasma. dUnbound clearance. eVolume of distribution at steady state. fHalf-life. gAUC, area under the curve. hOral bioavailability F was assessed following the administration of a 10 mg/kg dose (compounds 34c and 52c) or 1 mg/kg dose(compound 49e).iNot determined.
The anti-staphylococcal activity of compound 49e was confirmed in vivo in a neutropenic murine thigh infection model52 (MIC S. aureus = 0.06 mg/L). When administered subcutaneously at a dose of 40 mg/kg, 49e mediated a net 1-log reduction of colony forming units (CFU) in the thigh measured 6 h post infection. CONCLUSION We have reported the design of novel bacterial dual DNA gyrase and Topo IV inhibitors comprising a tetrahydropyran core and have elaborated SAR findings that led us to identify an ethylene-diol motif as a suitable moiety connecting the central THP-ring to the LHS. Our efforts to optimize antibacterial and pharmacological profile and simultaneously decrease block of hERG K+ channel have resulted in synthesis and characterization of a series of potent dual GyrA/ParC inhibitors which display strong antibacterial activity against clinically relevant pathogens such as Staphylococci, Enterococci, and Streptococci. Furthermore, we have demonstrated that dual inhibition of gyrase and Topo IV is required to minimize the rate of resistance development. Although a fully balanced GyrA/ParC inhibition profile could be achieved, our efforts to further advance such balanced inhibitors were thwarted by unacceptable hERG K+ channel block. However, we have identified compound 49e which shows an exquisite antibacterial profile, while having a low to moderate resistance frequency in vitro
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and significantly decreased hERG K+ channel block. The pharmacokinetic parameters of 49e were sufficient to reach exposures needed for in vivo efficacy in a murine thigh infection model. THP-based bacterial topoisomerase inhibitors show promising properties and deserve further efforts to be eventually transformed into new clinically used antibacterial agents.
EXPERIMENTAL SECTION MIC testing. Minimal inhibitory concentrations (MICs) were determined by the broth microdilution method according to guidelines of the Clinical and Laboratory Standards Institute (CLSI)28. Stock solutions of compounds were prepared in DMSO and serially diluted in cation-adjusted MuellerHinton broth (final DMSO concentration, 2.5 % (v/v). Reference antibiotics (ciprofloxacin, linezolid) were tested in parallel and MICs against quality control strains were within the accepted CLSI ranges.
Spontaneous resistance frequencies. Large numbers of bacteria (109-1010) were plated on Mueller-Hinton agar plates containing the antibiotic compound at 4- and 16-fold the MIC concentration. Resistance frequencies were calculated by dividing the numbers of colonies growing after 48 h of incubation at 37°C through the total numbers of viable bacteria plated (as determined by colony count on drug-free agar).
DNA gyrase and Topo IV inhibition assays. DNA gyrase supercoiling inhibition assay was performed with relaxed pBR322 (purchased from Inspiralis, UK) as a substrate. For E. coli, the reaction mixture (20 µL) contained 25 mM Tris HCl pH 7.5, 24 mM KCl, 4 mM MgCl2, 2 mM DTT, 1 mM ATP, 1.6 mM spermidine, 6.5% glycerol, 50 µg/mL Bovine Serum Albumin (BSA) and 0.1 µg relaxed plasmid. For S. aureus the reaction mixture (20 µL) contained 50 mM Tris HCl pH 7.5, 20 mM KCl, 5 mM MgCl2, 5 mM DTT, 3 mM ATP, 700 mM potassium glutamate, 50 µg/mL BSA and 0.1 µg relaxed plasmid. The reactions were carried out at 37 °C for 1 h. DNA Topo IV relaxation assay was performed with supercoiled pBR322 as a substrate. For E. coli, the reaction mixture (20 µL) contained 50 mM Tris HCl pH 7.8. 20 mM KCl, 6 mM MgCl2, 10 mM DTT, 1 mM ATP, 1 mM
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spermidine, 100 µg/mL BSA and 0.1 µg supercoiled pBR322. For S. aureus, the reaction mixture (20 µL) contained 50 mM Tris HCl pH 7.5. 20 mM KCl, 5 mM MgCl2, 5 mM DTT, 1.5 mM ATP, 5 mM spermidine, 100 mM potassium glutamate, 5 µg/mL BSA and 0.1 µg supercoiled pBR322. The reaction was carried out at 37 °C for 1 h. Both supercoiling and relaxation reactions were stopped by adding a mixture of EDTA, bromophenol blue and glycerol. 10 µL of each reaction mixture were loaded on a 1% agarose gel in TAE buffer (40 mM Tris-acetate, 1 mM EDTA pH 8.0) and run at 1.0 V/cm for 14 to 16 h. Gels were stained in water with ethidium bromide and visualized under ultraviolet light. For supercoiling inhibition assays (SCIA), 50% inhibitory concentration (IC50) was determined visually as being the compound concentration at which the supercoiled band was reduced by 50%. For relaxation inhibition assays (RIA), IC50 was defined as the concentration of inhibitor necessary to inhibit the formation of 50% relaxed DNA from supercoiled. The IC50 was taken as an average of two inhibitory concentrations if inhibition did not occur exactly within a particular concentration range (for representative gels, see Supporting Information) . All gels were also subject to analysis using AlphaEase Stand Alone Software (Alpha Innotech).
hERG assays53. Compounds were evaluated for block of the hERG K channel using CHO cells stably expressing the hERG gene (bSys, Witterswil, Switzerland) and the QPatch platform (Sophion, Ballerup, Denmark). K tail currents were measured at -40 mV following a 500-ms depolarization to +20 mV from a holding voltage of -80 mV. The external solution contained 4 mM K+, 1 mM Mg2+ and 1.2 mM Ca2+. Compound effects were quantified 3 minutes after application to the cells.
Mice, in life procedures. All animal housing and experiments were performed in agreement with the Swiss Federal Ordinance for animal protection, the animal welfare guide lines from the Cantonal Vetenary Office Basellandschaft, and the Actelion Pharmaceuticals Ltd internal animal welfare guidelines. Eight to twelve week-old, specific pathogen-free, female NMRI mice weighing 27 to 30 g were used for all studies (Harlan, The Netherlands). Mice were rendered neutropenic (neutrophils < 100/mm3) by injecting cyclophosphamide (Sigma) intraperitoneally 4 days (150 mg/kg) and 1 day
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(100 mg/kg) before thigh infection. Previous studies have shown that this regimen produces neutropenia in this model for 5 days. Broth cultures of freshly plated S. aureus (laboratory descendent of DSM 11823) were grown to logarithmic phase overnight to an absorbance of 0.3 to 0.9 at 580 nm. Thigh infections with S. aureus were performed by injection of 0.05 ml of inoculum (107.0-8.0 CFU/ml) intra muscularly into both thighs of mice 2 h before administration of compound 49e (formulated in 5% mannitol in water, administered at 10 ml/kg). Post-mortem, thigh samples were homogenized (Ultra-Turrax® tube drive - IKA), serially diluted and plated (spiral platter EddyJet® (IUL)). Results were expressed as colony forming units (CFU; CFU-counter Flash & Grow® - IUL), correlating to remaining bacterial load in the thigh at the end of the study.
Pharmacokinetics in the Rat. The pharmacokinetic profile was determined in the male Wistar rat (n = 3). For this purpose, compound 34c was formulated as an aqueous solution at pH 4.5 for intravenous administration at a dose of 1 mg/kg and as aqueous suspension pH 5.6 for oral dosing at 10 mg/kg; compound 49e was formulated as a solution in 5% DMSO in pure water for intravenous administration at a dose of 0.5 mg/kg, and as a microsuspension in 7.5% aqueous modified gelatin for oral dosing at 1 mg/kg; compound 52c was formulated as a solution in 10 % PG, 10% PEG400 in water at pH 7 for intravenous administration at a dose of 1 mg/kg and as a microsuspension in 0.5% in methylcellulose for oral dosing at 10 mg/kg. Blood samples were taken at regular time intervals over a period of 24 h from a preimplanted catheter, and plasma was generated by centrifugation at 4000 rpm at 4 °C. Plasma concentrations were determined using a specific and sensitive LCMS/ MS method with a limit of quantification of 1.5 ng/mL.
General Chemical Methods. Starting materials, reagents and solvents were obtained from commercial sources and used as received. All reactions were carried out with continuous stirring under atmosphere of dry nitrogen. The resonance frequency for 1H (13C) on a Varian Gemini 300 is 300MHz (75MHz). Chemical shifts (δ) are reported in parts per million (ppm) relative to deuterated solvent as the internal standard (δH: CDCl3 7.26ppm, DMSO-d6 2.50ppm), coupling constants (J) are in hertz
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(Hz). Peak multiplicities are expressed as follows: singlet (s), doublet (d), doublet of doublets (dd), triplet (t), quartet (q), multiplet (m), broad singlet (br s). Melting points were recorded with a Büchi 520 apparatus and are uncorrected. Purification of intermediates and final products was carried out on normal phase using an ISCO CombiFlash system and prepacked SiO2 cartridges eluted with optimized gradients of either heptane-ethyl acetate mixture or dichloromethane-methanol (doped with 1% v/v of aq NH4OH for basic compounds). Progress of the reactions was monitored by thin-layer chromatography (TLC) analysis (Merck, 0.2 mm silica gel 60 F254 on glass plates) or by LC-MS (Methods and equipments are described in Supporting Information). Unless otherwise stated, all target compounds had purity > 95%, established on a Waters Atlantis T3, 5 µm, 4.6 mm × 30 mm, eluting with a gradient of 5−95% of acetonitrile in water containing 0.04% of trifluoroacetic acid; or on a Waters XBridge C18, OBD, 5 µm, 4.6 mm × 50 mm (Waters, Switzerland), eluting with a gradient of 5−95% of acetonitrile in water containing 13 mM of NH4OH UV at 230 nm and 254nm. Purity and identity were further confirmed by NMR spectroscopy. Optical rotations were measured on a Jasco P1030 apparatus. HPLC-HRMS Methods and equipments are described in Supporting Information. Retention times (tR) are expressed in minutes. Personal protective equipment (mask and gloves) should be worn when handling aldehydes 19b-27b (irritant). Compound 23a is commercially available.
tert-butyl ((2S)-1-hydroxy-4-(oxiran-2-yl)butan-2-yl)carbamate (9). To a suspension of LiBH4 (1.15 g, 53 mmol) in THF (300 mL) at rt was added a solution of 830 (12.9 g, 53 mmol) in THF (100 mL). The mixture was stirred at rt for 4 h, poured into water and extracted with EtOAc. The organic layer was washed with brine, dried over MgSO4 and concentrated to give the alcohol (11.4 g, 99% yield). Colorless oil; 1H NMR δ (CDCl3): 5.75-5.65 (m, 1H), 5.00-4.90 (m, 2H), 4.5 (br, 1H, OH), 3.70-3.45 (m, 3H), 2.10-2.00 (m, 2H), 1.60-1.35 (m, 2H), 1.38 (s, 9H). The latter (11.4 g, 53 mmol) was dissolved in DCE (300 mL) and water (250 mL) and 1 M phosphate buffer pH 8 (150 mL) was added. m-CPBA (14.3 g) was added and the mixture vigorously stirred overnight. The two phases were separated and the aq phase was extracted once more with DCM. The combined organic layers were washed with a saturated NaHCO3 solution, dried over MgSO4, filtered and concentrated to
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dryness. The residue was purified by chromatography (heptane-EtOAc) to give 9 (7.74 g, 63% yield, mixture of diastereomers). Colorless oil; 1H NMR δ (CDCl3): 4.85-4.90 (m, 1H), 3.50-3.75 (m, 3H), 2.90-3.00 (m, 1H), 2.51-2.80 (m, 1H), 2.6 (br, 1H, OH), 2.50-2.55 (m, 1H), 1.40-1.80 (m, 4H), 1.42 (s, 9H).
tert-butyl ((3S,6R)-6-(hydroxymethyl)tetrahydro-2H-pyran-3-yl)carbamate (ent-7). A solution of the epoxide 9 (2.3 g, 10 mmol) in DCM (50 mL) was treated with CSA (0.23 g, 1 mmol). The mixture was stirred at rt for 3 h, diluted with a saturated NaHCO3 solution (100 mL). The two layers were separated and the organic layer was dried over Na2SO4, filtered and concentrated to dryness. The residue was purified by chromatography (EtOAc) to give ent-7 (0.874 g, 37% yield). Colorless solid; m.p.= 112.9 °C; [α]D= + 7.1 (c 0.96, MeOH); 1H NMR δ (CDCl3): 4.28 (br, 1H), 4.104.20-10 (m, 1H), 3.30-3.70 (m, 5H), 3.04 (t, J =10.6 Hz, 1H), 2.00-2.20 (m, 2H), 1.20-1.75 (m, 11H); 13
C NMR δ (DMSO-d6) 155.6, 78.5, 78.3, 70.9, 65.0, 47.1, 29.8, 28.9 (3C), 27.8;; ESI-MS (M+H)+
m/z 232.2; HR ESI-MS (M+Na)+ m/z = 254.1370 (calc. for C11H21NO4Na: 254.1368); tR = 0.84.
tert-butyl ((3R,6S)-6-carbamoyltetrahydro-2H-pyran-3-yl)carbamate (12). To a solution of 11 (3 g, 12.2 mmol, prepared from 7 as described29) in EtOAc (50 mL) was added NHS (1.5 g, 13 mmol) and DCC (2.7 g, 13.1 mmol). The reaction was stirred overnight at rt. After filtration and concentration to dryness, the residue was taken up in THF (180 mL). Gaseous NH3 was bubbled through the solution for 10 min, and the reaction proceeded at rt for 1 h. Silica gel (20 g) was added, and the volatiles were removed in vacuo. The residue was purified by chromatography (DCM-MeOH 19-1) to afford 12 (1.3 g, 43%). White solid; 1H NMR δ (DMSO-d6): 7.15 (br s, 1H), 7.07 (br s, 1H), 6.83 (d, J = 8.0 Hz, 1H), 3.85 (m, 1H), 3.56 (m, 1H), 3.32 (m, 1H), 3.01 (t, 10.6 Hz, 1H), 1.84-1.96 (m, 2H), 1.34-1.43 (m, 2H), 1.36 (s, 9H); 13C NMR δ (DMSO-d6): 173.2, 155.5, 78.3, 76.9, 70.4, 46.5, 29.6, 28.7 (3C), 28.5; HR ESI-MS (M+H)+ m/z = 245.1502 (calc. for C11H21N2O4: 245.1501); tR = 0.82.
(tert-butyl ((3R,6S)-6-formyltetrahydro-2H-pyran-3-yl)carbamate (13). To a solution of 7 (37.5 g, 162.13 mmol) in DCM (310 mL) cooled to -10°C was added DIPEA (84.75 mL, 495 mmol).
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A solution of py.SO3 complex (69.47 g, 218 mmol) in DMSO (225 mL) was slowly added. The reaction mixture was stirred for 2 h at 0 °C .The reaction mixture was partitioned between water (150 mL) and DCM (220 mL). The two layers were separated and the aq layer was extracted twice with DCM (2 x 150 mL). The combined organic layers were dried over Na2SO4, filtered and concentrated to dryness. The residue was filtered through silica gel (EtOAc-heptane) to afford 13 (33.58 g, 90%). White solid; m.p.= 108.9 °C; 1H NMR δ (CDCl3): 9.63 (br s, 1H), 4.37 (br s, 1H), 4.16 (ddd, J = 1.7, 4.5, 10.9 Hz, 1H), 3.72 (dd, J = 2.9, 10.7 Hz, 1H), 3.62 (br s, 1H), 3.14 (t, J = 10.4 Hz, 1H), 2.12 (m, 1H), 1.96 (m, 1H), 1.56 (m, 1H), 1.44 (s, 9H), 1.38 (overlaid m, 1H);13C NMR δ (CDCl3): 201.3, 155.1, 80.6, 79.7, 70.8, 45.9, 29.2, 28.4 (3C), 25.0; ESI-MS (M+H)+ m/z 230.0; HR ESI-MS (M+Na)+ m/z = 252.1214 (calc. for C11H19NO4Na: 252.1211); tR = 0.78.
tert-butyl ((3R,6S)-6-vinyltetrahydro-2H-pyran-3-yl)carbamate (14). t-BuOK (31.74 g, 282.89 mmol) was added in one portion to a white suspension of methyltriphenylphosphonium bromide (101.05 g, 282.89 mmol) in THF (340 mL) at rt under nitrogen. The resulting suspension was stirred for 1 h at rt and a solution of 13 (32.43 g, 141.44 mmol) in THF (85 mL) was added. The mixture was stirred 30 min. at rt. A 10% NaHSO4 solution (120 mL) was added and the mixture was diluted with EtOAc (200 mL). The two layers were decanted and the aq layer was extracted once with EtOAc (250 mL). The combined organic layers were washed with brine, dried over Na2SO4, filtered and concentrated to dryness. The residue was purified by chromatography (heptane-EtOAc) to afford 14 (28.98 g, 90%). White solid; 1H NMR δ (CDCl3): 5.84 (ddd, J = 5.6, 10.5, 17.3 Hz, 1H), 5.24 (dt, J = 1.5, 17.3 Hz, 1H), 5.12 (dt, J = 1.5, 10.5 Hz, 1H), 4.26 (br. s, 1H), 4.10 (ddd, J = 2.1, 4.7, 10.8 Hz, 1H), 3.73 (m, 1H), 3.61 (m, 1H), 3.06 (t, J = 10.5 Hz, 1H), 2.10 (m, 1H), 1.79 (m, 1H), 1.25-1.60 (m, 2H), 1.44 (s, 9H); ESI-MS (M+H)+ m/z= 228.2.
tert-butyl ((3R,6S)-6-(2-oxoethyl)tetrahydro-2H-pyran-3-yl)carbamate (15). To an icechilled solution of 14 (1.47 g, 6.46 mmol) in THF (30 mL) was added 9-BBN-H (2.37 g, 19.4 mmol). The mixture was stirred overnight at rt. After cooling to 0 °C, 3 N NaOH (25 mL) and 50% aq H2O2 (12 mL) were cautiously added. The resulting mixture was stirred at rt for 2 h. The two layers were decanted and the aq layer was extracted with EtOAc (2 x 200 mL). The combined organic layers were
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washed with 10% aq NaHSO3 solution (100 mL), water (50 mL) and dried over Na2SO4. After filtration and concentration to dryness, the residue was purified by chromatography (heptane-EtOAc) to afford the resulting alcohol (1.15 g, 72%). White solid; 1H NMR δ (CDCl3): 4.16 (br s, 1H), 4.01 (ddd, J = 2.2, 4.7, 10.7 Hz, 1H), 3.69 (t, J = 5.2 Hz, 2H), 3.52 (br s, 1H), 3.39 (m, 1H), 2.93 (t, J = 10.7 Hz, 1H), 2.02 (br s, 1H), 2.00 (m, 1H), 1.58-1.72 (m, 3H), 1.45 (m, 1H), 1.37 (s, 9H), 1.24 (qd, J = 4.1, 12.2 Hz, 1H); ESI-MS (M+H)+ m/z 246.4. The latter alcohol (1.15 g, 4.68 mmol) was dissolved in DCM (20 mL), and after cooling to 0 °C, a solution of Dess-Martin periodinane (15 wt% in DCM, 18 mL) was added. After warming to rt, the reaction proceeded for 2 h. The reaction mixture was concentrated to dryness and the residue purified by chromatography (heptane-EtOAc) to afford 15 (1.06 g, 93%). White solid; 1H NMR δ (CDCl3): 9.79 (t, J = 2.3 Hz, 1H), 4.29 (br s, 1H), 4.07 (ddd, J = 2.1, 4.7, 10.7 Hz, 1H), 3.77 (m, 1H), 3.61 (br s, 1H), 3.04 (t, J = 10.7 Hz, 1H), 2.65 (ddd, J = 2.3, 7.6, 16.5 Hz, 1H), 2.49 (ddd, J = 2.3, 4.8, 16.5 Hz, 1H), 2.12 (m, 1H), 1.79 (m, 1H), 1.50 (overlaid m, 1H), 1.49 (s, 9H), 1.33 (qd, J = 4.1, 12.2 Hz, 1H); 13C NMR δ (CDCl3): 200.9, 155.1, 79.5, 72.3, 71.3, 49.2, 46.2, 30.7, 30.3, 28.3 (3C); HR ESI-MS (M+Na)+ m/z = 266.1367 (calc. for C12H21NO4Na: 266.1368); tR = 0.81.
tert-butyl ((3R,6S)-6-(iodomethyl)tetrahydro-2H-pyran-3-yl)carbamate (16). To an icechilled solution of 7 (40.9 g, 176.8 mmol)29 in DCM (840 mL) were added successively Et3N (59.5 mL, 423.9 mmol), DMAP (3.01 g, 24.56 mmol) and TsCl (42.4 g, 222.4 mmol). The reaction proceeded 4 h with warming to rt. A saturated NaHCO3 solution (350 mL) was added. The two phases were separated and the organic layer was evaporated in vacuo. The residue was diluted with EtOAc (900 mL) and the organic layer was washed three times with a saturated CuSO4 solution (3 x 200 mL), brine (200 mL), dried over MgSO4, filtered and concentrated to dryness to afford the crude tosylate (75.83 g); 1H NMR δ (CDCl3): 7.78 (d, J = 8.7 Hz, 2H), 7.33 (d, J = 8.7 Hz, 2H), 4.20 (br s, 1H), 4.01 (ddd, J = 2.1, 4.7, 10.8 Hz, 1H), 3.96 (d, J = 5.7 Hz, 2H), 3.54 (br s, 1H), 3.48 (m, 1H), 2.93 (t, J = 10.8 Hz, 1H), 2.44 (s, 3H), 2.09 (m, 1H), 1.69 (m, 1H), 1.48-1.18 (m, 2H), 1.42 (s, 9H); ESI-MS (M+H)+ m/z =386.2. The latter (75.83 g) was taken up in acetone (700 mL) and NaI (90.0 g, 600.4 mmol) was added. The reaction mixture was refluxed 24 h. The reaction mixture was cooled to rt and
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diluted with water (500 mL). The volatiles were removed in vacuo. The solid was filtered off, washed with water, partitioned between EtOAc (700 mL) and water (300 mL). The organic layer was dried over MgSO4, filtered, evaporated in vacuo to afford 16 (59.7 g, 99%). White solid; m.p.= 128.9 °C; 1H NMR δ (CDCl3): 4.20 (br. s, 1H), 4.10 (ddd, J = 2.1, 4.8, 10.8 Hz, 1H), 3.60 (br. s, 1H), 3.28 (m, 1H), 3.17 (d, J = 6.3 Hz, 2H), 3.04 (t, J = 10.8 Hz, 1H), 2.10 (m, 1H), 1.94 (m, 1H), 1.44-1.20 (m, 2H), 1.43 (s, 9H);
13
C NMR δ (CDCl3): 155.3, 79.7, 76.7, 71.5, 46.4, 30.8, 30.2, 28.6 (3C), 8.7; HR ESI-MS
(M+H-C4H8)+ m/z = 285.9943 (calc. for C7H13NO3I: 285.9940); tR = 1.26.
tert-butyl ((3R,6S)-6-(((1-phenyl-1H-tetrazol-5-yl)thio)methyl)tetrahydro-2H-pyran-3yl)carbamate (17). To a mixture of PT-SH (37.50 g, 210.4 mmol) in EtOH (700 mL) was added powdered KOH (14.0 g, 249.5 mmol). The mixture was refluxed for 1 h and a solution of 16 (59.40 g, 174.1 mmol) in EtOH (500 mL) was added. The reaction mixture was refluxed overnight. Water (400 mL) was added and the volatiles were removed in vacuo. The solid was filtered off, washed with water and dried to afford 17 (59.68 g). White solid; 1H NMR δ (CDCl3): 7.51-7.62 (m, 5H), 4.21 (br. s, 1H), 4.07 (ddd, J = 2.1, 4.6, 10.8 Hz, 1H), 3.62-3.71 (m, 2H), 3.57 (br. s, 1H), 3.34 (m, 1H), 2.99 (t, J = 10.8 Hz, 1H), 2.11 (m, 1H), 1.90 (m, 1H), 1.50 (m, 1H), 1.42 (s, 9H), 1.32 (qd, J = 3.8, 12.2 Hz, 1H); ESI-MS (M+H)+ m/z = 392.5.
tert-butyl
((3R,6S)-6-(((1-phenyl-1H-tetrazol-5-yl)sulfonyl)methyl)tetrahydro-2H-
pyran-3-yl)carbamate (18). 17 (59.68 g, 152.4 mmol) was dissolved in THF (400 mL) and EtOH (400 mL). A solution of (NH4)6Mo7O24.4H2O (18.9 g, 15.29 mmol) in 50% aq H2O2 (87 mL, 1.53 mol) was added at rt and the reaction mixture was heated to 65 °C for 3 h, cooled down to rt and diluted with water (500 mL). The volatiles were removed in vacuo. The residue was extracted with EtOAc (2 x 500 mL). The combined organic layers were washed with 10% aq Na2S2O3 solution (3 x 400 mL), a saturated NaHSO3 solution (3 x 400 mL), water (200 mL) and brine (200 mL), dried over MgSO4, filtered and concentrated to dryness. The solid was recrystallized from an EtOAc-heptane mixture to afford 18 (63.72 g, 86%). White solid; m.p.= 122.7 °C; 1H NMR δ (DMSO-d6): 7.64-7.74 (m, 5H), 6.72 (d, J = 7.9 Hz, 1H), 4.04 (d, J = 13.6 Hz, 1H), 3.61-3.76 (m, 2H), 3.53 (dd, J = 2.7, 9.6 Hz, 1H), 3.23 8br s, 1H), 2.88 (t, J = 10.8 Hz, 1H), 1.82 (br s, 1H), 1.65-1.72 (m, 1H), 1.30-1.41 (m, 2H), 1.36
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(s, 9H);
13
C NMR δ (CDCl3): 155.0, 154.0, 133.0, 131.5 (2C), 129.6 (3C), 125.9, 79.8, 71.4, 70.9,
60.8, 45.6, 30.0, 29.8, 28.4 (3C); HR ESI-MS (M+H)+ m/z = 424.1660 (calc. for C18H26N5O5S: 424.1654); tR = 1.27.
tert-butyl
((3S,6R)-6-(((1-phenyl-1H-tetrazol-5-yl)sulfonyl)methyl)tetrahydro-2H-
pyran-3-yl)carbamate (ent-18). Compound ent-18 (5.9 g) was obtained starting from ent-7 (8.2 g, 35.5 mmol) and using the procedures reported for the preparation of 18. Colorless solid; NMR identical to 18; ESI-MS (M+H)+ m/z = 424.4.
tert-butyl
((3R,6S)-6-(((6-methoxy-1,5-naphthyridin-4-yl)oxy)methyl)tetrahydro-2H-
pyran-3-yl)carbamate (28a). To a solution of 7 (1 g, 4.32 mmol), 23e26 (0.92 g, 5.2 mmol) and PPh3 (1.71 g, 6.5 mmol) in THF (32 mL) and DMF (2.2 mL) was added drop wise DIAD (1.32 g, 6.5 mmol). The reaction mixture was stirred at rt for 4 h and concentrated to dryness. The residue was diluted with 0.2 N HCl (110 mL) and the aq. layer was washed with Et2O. The pH was made basic with 1 N NaOH (22 mL) and the aq layer was extracted twice with EtOAc. The combined organic layers were washed with brine and dried over Na2SO4, filtered and concentrated. The residue was recrystallized from EtOAc to afford 28a (0.5 g, 1.28 mmol, 30% yield). Yellowish solid; m.p.= 173 °C; 1H NMR δ (DMSO-d6): 8.57 (d, J = 5.2 Hz, 1H), 8.17 (d, J = 9.0 Hz, 1H), 7.21 (d, J = 9.0 Hz, 1H), 7.18 (d, J = 5.2 Hz, 1H), 6.77 (m, 1H), 4.14-4.29 (m, 2H), 3.99 (s, 3H), 3.82 (m, 1H), 3.67 (m, 1H), 3.36 (m, 1H), 3.10 (t, J = 10.5 Hz, 1H), 1.81-1.97 (m, 2H), 1.33-1.63 (m, 2H), 1.36 (s, 9H); 13C NMR (CDCl3) δ: 161.5, 159.7, 155.2, 148.7, 142.7, 139.9, 134.3, 116.5, 105.5, 79.5, 75.1, 71.4, 71.3, 53.7, 46.4, 30.1, 28.4 (3C), 27.5; ESI-MS (M+H)+ m/z =390.2.
General Procedure A: Boc deprotection A solution of the Boc-protected amine (1 eq.) in TFA (2 mL/mmol) was stirred at rt for 1 h. The solvent was evaporated in vacuo, and the residue was partitioned between DCM-MeOH mixture (9-1, 10 mL/mmol) and saturated NaHCO3 solution (5 mL/mmol). The pH was adjusted to 10 adding 32% aq NaOH. The two layers were separated and the aq layer was extracted three times with the same mixture (3 x 10mL/mmol) and the combined organic layers were dried over Na2SO4, filtered and
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concentrated to dryness. The residue was purified by chromatography (DCM-MeOH 19-1, containing 1% aq NH4OH) to afford the corresponding amine.
(3R,6S)-6-(((6-methoxy-1,5-naphthyridin-4-yl)oxy)methyl)tetrahydro-2H-pyran-3amine (28b). The compound 28b was prepared in 98% yield from 28a according to the general procedure A. Yellowish oil; 1H NMR δ (DMSO-d6): 8.57 (d, J = 5.3 Hz, 1 H), 8.17 (d, J = 9.0 Hz, 1 H), 7.22 (d, J = 9.0 Hz, 1 H), 7.18 (d, J = 9.0 Hz, 1 H), 4.15-4.29 (m, 2H), 3.99 (s, 3H), 3.85 (m, 1H), 3.70 (m, 1H), 3.04 (t, J = 10.4 Hz, 1H), 2.74 (m, 1H), 2.00 (m, 1H), 1.87 (m, 1H), 1.52 (m, 1H), 1.34 (m, 1H); 13C NMR δ (CDCl3): 161.6, 159.8, 148.7, 142.6, 139.9, 134.4, 116.6, 105.6, 75.2, 72.7, 71.5, 53.9, 47.3, 31.4, 27.3; ESI-MS (M+H)+ m/z = 290.4.
General method B: Reductive amination using aldehyde 32 or 33 To a solution of amine (1eq.) in DCE (10 mL/mmol) and MeOH (4 mL/mmol) were added 3 Å molecular sieves (3 g/mmol) and 32 or 33 (1.1eq.). The reaction was heated at 50 °C overnight. After cooling to 0 °C, NaBH4 (400 mol%) was added and the reaction was stirred for 2 h. The reaction mixture was filtered, and the filtrate was diluted with DCM-MeOH (9-1, 10 mL/mmol) and saturated NaHCO3 solution (5 mL/mmol). The two layers were separated and the organic layer was dried over dried over Na2SO4, filtered and concentrated to dryness. The residue was purified by chromatography (DCM-MeOH containing 1% aq. NH4OH) to afford the alkylated product.
6-((((3R,6S)-6-(((6-methoxy-1,5-naphthyridin-4-yl)oxy)methyl)tetrahydro-2H-pyran3-yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin-3(4H)-one (28c). The compound 28c was obtained in 55% yield from the compounds 28b and 32 according to the general procedure B. White solid; m.p.= 202 °C (degradation); 1H NMR δ (DMSO-d6): 10.8 (br s, 1H), 8.59 (d, J = 5.2 Hz, 1H), 8.20 (d, J = 9.0 Hz, 1H), 7.75 (d, J = 7.8 Hz, 1H), 7.24 (d, J = 9.0 Hz, 1H), 7.20 (d, J = 5.2 Hz, 1H), 7.10 (d, J = 7.9 Hz, 1H), 4.26 (dd, J = 6.0, 10.9 Hz, 1H), 4.19 (dd, J = 3.8, 10.9 Hz, 1H), 3.99 (s, 3H), 3.97 (partially overlaid m, 1H), 3.70-3.79 (m, 3H), 3.53 (s, 2H), 3.04 (t, J = 10.5 Hz, 1H), 2.14 (br s, 1H), 2.08 (m, 1H), 1.86 (m, 1H), 1.51 (m, 1H), 1.30 (m, 1H); 13C NMR δ (DMSO-d6): 166.6, 161.2, 159.7, 158.2, 149.5, 149.2, 142.6 , 140.6, 136.4, 134.1, 117.1, 116.7, 113.2, 106.5, 75.5, 72.2, 71.7,
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53.8, 53.4, 51.6, 30.5, 29.3, 27.4; HR ESI-MS (M+H)+ m/z = 468.1699 (calc. for C23H26N5O4S: 468.1705); tR = 0.91.
(3R,6S)-N-((2,3-dihydro-[1,4]dioxino[2,3-c]pyridin-7-yl)methyl)-6-(((6-methoxy-1,5naphthyridin-4-yl)oxy)methyl)tetrahydro-2H-pyran-3-amine (28d). The compound 28d was obtained in 51% yield from the compounds 28b and 33 according to the general procedure B. Colorless solid; 1H NMR δ (DMSO-d6): 8.57 (d, J = 5.2 Hz, 1 H), 8.17 (d, J = 9.0 Hz, 1 H), 7.99 (s, 1 H), 7.21 (d, J = 9.1 Hz, 1 H), 7.17 (d, J = 5.3 Hz, 1 H), 6.92 (s, 1 H), 4.30-4.34 (m, 2H), 4.24-4.28 (m, 2H), 4.13-4.24 (m, 2H), 3.97 (s, 3H), 3.94 (overlaid m, 1H), 3.72 (overlaid m, 1H), 3.67 (br s, 2H), 3.00 (t, J = 10.5 Hz, 1H), 2.50 (overlaid m, 1H), 1.99-2.10 (m, 2H), 1.83 (m, 1H), 1.47 (m, 1H), 1.26 (m, 1H); 13C NMR δ (CDCl3): 161.5, 159.8, 153.5, 150.2 , 148.8 , 142.8, 140.1, 140.0, 138.8, 134.4, 116.6, 110.6 , 105.6, 75.6, 72.7, 71.8, 65.0, 64.1, 53.7, 53. 4, 52.1, 30.7, 27.7; HR ESI-MS (M+H)+ m/z = 439.1988 (calc. for C23H27N4O5: 439.1981) ); tR = 0.89.
tert-butyl
((3R,6S)-6-((6-methoxy-1,5-naphthyridin-4-yl)carbamoyl)tetrahydro-2H-
pyran-3-yl)carbamate (29a). To a degassed mixture of 12 (0.8 g, 3.2 mmol), Cs2CO3 (1.3 g, 4 mmol), BINAP (0.145 g, 0.23 mmol) and (dba)3Pd2.CHCl3 (0.057 g, 0.055 mmol) was added dioxane (41 mL). 23a (0.76 g, 3.2 mmol) was added and the reaction proceeded overnight at 100 °C. After filtration, the filtrate was concentrated in vacuo and the residue was purified by chromatography (DCM-MeOH 19-1) to afford 29a (1.3 g, 99% yield). Beige foam; m.p.= 131.2 °C; 1H NMR δ (CDCl3): 10.57 (s, 1H), 8.70 (d, J = 5.2 Hz, IH), 8.51 (d, J = 5.2 Hz, 1H), 8.22 (d, J = 9.0 Hz, 1H), 7.16 (d, J = 9.0 Hz, 1H), 4.32 (m, 2H), 4.12 (s, 3H), 4.01 (dd, J = 2.5, 11.4 Hz, IH), 3.72 (m, IH), 3.23 (t, J = 10.6 Hz, 1H), 2.39 (qd, J = 2.8, 10.2 Hz, 1H), 2.22 (m, 1H), 1.76 (m, 1H), 1.47 (overlaid m, 1H), 1.47 (s, 9H): 13C NMR δ (CDCl3): 170.1, 161.4, 155.2, 149.1, 141.0, 140.5, 139.0, 132.2, 116.7, 110.8, 79.8, 77.1, 71.3, 53.2, 38.6, 30.0, 28.4 (3C), 28.0; HR ESI-MS (M+HH)+ m/z = 403.1985 (calc. for C20H27N4O5: 403.1981); tR = 0.84.
(2S,5R)-5-amino-N-(6-methoxy-1,5-naphthyridin-4-yl)tetrahydro-2H-pyran-2carboxamide (29b). The compound 29b was obtained in 80% yield from the compound 29a
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according to the general procedure A. Yellowish solid; m.p.= 205.7 °C; 1H NMR δ (DMSO-d6): 10.52 (s, 1 H), 8.72 (d, J = 5.0 Hz, 1 H), 8.40 (d, J = 5.0 Hz, 1 H), 8.30 (d, J = 9.1 Hz, 1 H), 7.35 (d, J = 9.1 Hz, 1 H), 5.31 (br s, 2H), 4.09-4.16 (m, 2H), 4.07 (s, 3H), 3.30 (overlaid m, 1H), 2.98 (m, 1H), 2.18 (m, 1H), 2.07 (m, 1H), 1.60 (m, 1H), 1.50 (m, 1H); 13C NMR δ (CDCl3): 170.3, 161.5, 149.5, 141.2, 138.8, 131.8, 117.3, 110.4 , 76.6 , 72.0, 53.9, 46.8 , 38.7, 30.7, 27.9; ESI-MS (M+H)+ m/z = 303.4.
(2S,5R)-N-(6-methoxy-1,5-naphthyridin-4-yl)-5-(((3-oxo-3,4-dihydro-2H-pyrido[3,2b][1,4]thiazin-6-yl)methyl)amino)tetrahydro-2H-pyran-2-carboxamide
(29c).
The
compound 29c was obtained in 27% yield from the compounds 29b and 32 according to the general procedure B. White solid; m.p.= 234 °C (degradation); 1H NMR δ (DMSO-d6): 10.8 (br s, 1H), 10.4 (br s, 1H), 8.68 (d, J = 5.0 Hz, 1H), 8.36 (d, J = 5.0 Hz, 1H), 8.26 (d, J = 9.2 Hz, 1H), 7.73 d J = 7.9 Hz, 1H), 7.31 (d, J = 9.2 Hz, 1H), 7.08 (d, J = 7.9 Hz, 1H), 4.15 (m, 1H), 4.05 (overlaid m, 1H), 4.02 (s, 3H), 3.74 (br s, 2H), 3.50 (s, 2H), 3.30 (overlaid m, 1H), 2.61 (m, 1H), 2.04-2.27 (m, 3H), 1.321.54 (m, 2H); HR ESI-MS (M+H)+ m/z =481.1656 (calc. for C23H25N6O4S: 481.1658); tR = 1.18.
(2S,5R)-5-(((2,3-dihydro-[1,4]dioxino[2,3-c]pyridin-7-yl)methyl)amino)-N-(6methoxy-1,5-naphthyridin-4-yl)tetrahydro-2H-pyran-2-carboxamide
(29d).
The
compound 29d was obtained in 55% yield from the compounds 29b and 33 according to the general procedure B. White solid; m.p.= 68.8 °C; 1H NMR δ (DMSO-d6): 10.51 (s, 1H), 8.70 (d, J = 5.0 Hz, 1H), 8.38 (d, J = 5.0 Hz, 1H), 8.28 (d, J = 9.0 Hz, 1H), 7.32 (d, J = 9.0 Hz, 1H), 7.25 (d, J = 7.9 Hz, 1H), 6.97 (d, J = 7.9 Hz, 1H), 4.38 (m, 2H), 4.22 (m, 2H), 4.18 (partially overlaid dd, J = 3.0, 10.6 Hz, 1H), 4.07 (partially overlaid m, 1H), 4.06 (s, 3H), 3.67 (dd, AB system, J = 14.6 Hz, 2H), 3.25 (t, J = 10.6 Hz, 1H), 2.61 (m, 1H), 2.15 (m, 3H), 1.56-1.36 (m, 2H); HR ESI-MS (M+H)+ m/z =452.1932 (calc. for C23H26N5O5: 452.1933) ; tR = 1.17.
tert-butyl
((3R,6S)-6-(2-hydroxy-2-(6-methoxy-1,5-naphthyridin-4-
yl)ethyl)tetrahydro-2H-pyran-3-yl)carbamate (30a). To a solution of 23a (5.88 g, 24.6 mmol) in THF (75 mL), cooled to -78 °C, was added quickly n-butyl lithium (2.35N in Heptane, 10.2 mL). The mixture was stirred at -78 °C for 15 min and a solution of 15 (2.0 g, 8.22 mmol) in THF (10 mL)
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was added. After 5 min, 10% aq NaHSO4 solution (20 mL) and EtOAc (10 mL) were added. The two layers were decanted and the aq layer was extracted with EtOAc (2 x 100 mL). The combined organic layers were washed with brine, dried over Na2SO4, filtered and concentrated to dryness. The residue was purified by chromatography (heptane-EtOAc) to yield 30a (1.6 g, 48% yield, 1:1 mixture of epimers). Yellowish foam; ESI-MS (M+H)+ m/z = 404.1.
2-((2S,5R)-5-aminotetrahydro-2H-pyran-2-yl)-1-(6-methoxy-1,5-naphthyridin-4yl)ethan-1-ol (30b). The compound 30b was prepared in 37% yield from the compound 30a according to the general procedure A. 30b was recovered as a 1:1 mixture of epimers. Colorless foam; ESI-MS (M+H)+ m/z = 304.2.
6-((((3R,6S)-6-(2-hydroxy-2-(6-methoxy-1,5-naphthyridin-4-yl)ethyl)tetrahydro-2Hpyran-3-yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin-3(4H)-one (30c). The compound 30c was obtained in 71% yield from the compounds 30b and 32 according to the general procedure B. Yellowish foam; 1H NMR δ (DMSO-d6) mixture of epimers: 10.86 (s, 1H), 8.77 (d, J = 4.6 Hz, 0.5H), 8.75 (d, J = 4.6 Hz, 0.5H), 8.25 (d, J = 9.1 Hz, 0.5H), 8.24 (d, J = 9.1 Hz, 0.5H), 7.75-7.71 (m, 2H), 7.25 (d, J = 9.1 Hz, 0.5H), 7.23 (d, J = 9.1 Hz, 0.5H), 7.08 (d, J = 7.8 Hz, 0.5H), 7.06 (d, J = 7.8 Hz, 0.5H), 5.74 (m, 0.5H), 5.63 (m, 0.5H), 5.39 (d, J = 4.9 Hz, 0.5H), 5.35 (d, J = 5.2 Hz, 0.5H), 4.01 (s, 1.5H), 4.00 (s, 1.5H), 4.00-3.79 (m, 1H), 3.71 (br s, 2H), 3.52 (s, 2H), 3.52 (overlaid m, 0.5H), 3.43 (m, 0.5H), 2.96 (t, J = 10.3 Hz, 0.5H), 2.90 (t, J = 10.5 Hz, 0.5H), 2.46 (m, 1H), 2.08-1.74 (m, 4H), 1.64-1.55 (m, 1H), 1.31-1.14 (m, 2H); HR ESI-MS (M+H)+ m/z =482.1859 (calc. for C24H28N5O4S: 482.1862); tR = 1.15.
2-((2S,5R)-5-(((2,3-dihydro-[1,4]dioxino[2,3-c]pyridin-7-yl)methyl)amino)tetrahydro2H-pyran-2-yl)-1-(6-methoxy-1,5-naphthyridin-4-yl)ethan-1-ol (30d). The compound 30d was obtained in 52% yield from the compounds 30b and 33 according to the general procedure B. White foam; 1H NMR δ (DMSO-d6) mixture of epimers : 8.74 (d, J = 4.6 Hz, 0.5H), 8.73 (d, J = 4.6 Hz, 0.5H), 8.20-8.24 (two overlaid d, J = 9.1 Hz, 2x0.5H), 7.98 (s, 0.5H), 7.97 (s, 0.5H), 7.70-7.73 (two overlaid d, J = 4.6 Hz, 2x0.5H), 7.19-7.24 (two overlaid d, J = 9.1 Hz, 2x0.5H), 6.90 (s, 0.5H),
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6.89 (s, 0.5H), 5.73 (m, 0.5H), 5.61 (m, 0.5H), 5.35 (d, J = 5.0 Hz, 0.5H), 5.32 (d, J = 5.2 Hz, 0.5H), 4.28-4.33 (m, 2H), 4.23-4.27 (3, 2H), 3.98 (s, 3x0.5H), 3.97 (s, 3x0.5H), 3.77-3.91 (m, 1H), 3.58-3.70 (m, 2H), 3.36-3.54 (m, 1H), 2.92 (t, J = 10.3 Hz, 0.5H), 2.86 (t, J = 10.5 Hz, 0.5H), 2.37-2.50 (m, 1H), 2.11 (br s, 1H), 1.77-2.02 (m, 3H), 1.49-1.63 (m, 1H), 1.12-1.28 (m, 2H); HR ESI-MS (M+H)+ m/z =453.2135 (calc. for C24H29N4O5: 453.2137) ; tR = 1.17.
General Procedure C: Julia-Kocieński coupling to form (E)-alkenes To a solution of 18 or ent-18 (1 eq.) and the appropriate aldehyde (1 eq.) in DME (5 mL/mmol), cooled to -60 °C, was added drop wise KHMDS (0.5 M in toluene, 1.8 eq.) or LiHMDS (1 M in THF, 1.8eq.) over 30 min. The mixture was then allowed to warm up slowly to rt. After 45 min., water (10 mL/mmol) and EtOAc (10 mL/mmol) were added. The two layers were decanted and the aq. layer was extracted twice with EtOAc (2 x 10 mL/mmol). The combined organic layers were washed with brine, dried over Na2SO4 and concentrated to dryness. The residue was triturated in tert-butyl methyl ether (10 mL/mmol), filtered and dried to afford the corresponding (E)-alkene.
tert-butyl
((3R,6S)-6-((E)-2-(6-methoxy-1,5-naphthyridin-4-yl)vinyl)tetrahydro-2H-
pyran-3-yl)carbamate (31a). The compound 31a was prepared in 68% yield from 23b and 18 (KHMDS) according to the general procedure C. Off-white solid; m.p.= 180.9 °C; 1H NMR δ (DMSO-d6): 8.72 (d, J = 4.7 Hz, 1H), 8.25 (d, J = 9.0 Hz, 1H), 7.84 (d, J = 4.7 Hz, 1H), 7.55 (d, J = 16.5 Hz, 1H), 7.28 (d, J = 9.0 Hz, 1H), 6.93 (dd, J = 5.3 Hz, 16.5 Hz, 1H), 6.85 (d, J = 7.7 Hz, 1H), 4.04 (s, 3H), 4.01 (partially overlaid m, 1H), 3.90 (m, 1H), 3.39 (br s, 1H), 3.10 (t, J = 10.6 Hz, 1H), 1.89 (m, 2H), 1.50 (m, 2H), 1.39 (s, 9H); 13C NMR δ (CDCl3): 161.5, 155.2, 147.6, 142.3, 140.6, 140.3, 139.3, 135.5, 124.5, 119.4, 116.5, 84.3, 79.5, 77.4, 71.1, 53.7, 46.3, 30.9, 30.3, 28.4 (3C); HR ESI-MS (M+H)+ m/z = 386.2081 (calc. for C21H28N3O4: 386.2080); tR = 1.24.
tert-butyl
((3S,6R)-6-((E)-2-(6-methoxy-1,5-naphthyridin-4-yl)vinyl)tetrahydro-2H-
pyran-3-yl)carbamate (ent-31a). Compound ent-31a was prepared in 75% yield from 23b and ent-18 using the general procedure C (KHMDS). Colorless solid; 1H NMR (DMSO-d6) δ: 8.70 (d, , J =4.6 Hz, 1H), 8.23 (d, J =9.1 Hz, 1H), 7.82 (d, J = 4.6 Hz, 1H), 7.54 (d, J = 16.3 Hz, 1H), 7.26 (d, J =
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9.1 Hz, 1H), 6.91 (dd, J = 5.3, 16.3 Hz, 1H), 6.88 (br s, 1H), 4.03 (s, 3H), 3.95-4.05 (m, 1H), 3.803.90 (m, 1H), 3.35-3.45 (m, 1H), 3.08 (t, J =10.6 Hz, 1H), 1.80-2.00 (m, 2H), 1.40-1.60 (m, 2H), 1.36 (s, 9H) ; ESI-MS (M+H)+ m/z = 386.2.
(3R,6S)-6-((E)-2-(6-methoxy-1,5-naphthyridin-4-yl)vinyl)tetrahydro-2H-pyran-3amine (31b). The compound 31b was prepared in 80% yield from the compound 31a according to the general procedure A. Yellowish foam; 1H NMR δ (DMSO-d6): 8.70 (d, J = 4.7 Hz, 1 H), 8.23 (d, J = 9.1 Hz, 1 H), 7.81 (d, J = 4.7 Hz, 1 H), 7.51 (dd, J = 0.5, 16.3 Hz, 1 H), 7.26 (d, J = 9.1 Hz, 1 H), 6.92 (dd, J = 5.3, 16.4 Hz, 1 H), 4.03 (s, 3H), 3.97 (overlaid m, 1H), 3.85 (m, 1H), 2.99 (t, J = 10.4 Hz, 1H), 2.62 (m, 1H), 1.92 (m, 1H), 1.84 (m, 1H), 1.21-1.51 (m, 4H); 13C NMR δ (CDCl3): 161.4, 147.6, 142.2, 140.7, 140.2, 139.2, 136.1, 124.2, 119.5, 116.4, 77.5, 74.9, 53.8, 47.3, 33.7, 31.3; HR ESI-MS (M+H)+ m/z = 286.1554 (calc. for C16H20N3O2: 286.1555); tR = 0.62.
6-((((3R,6S)-6-((E)-2-(6-methoxy-1,5-naphthyridin-4-yl)vinyl)tetrahydro-2H-pyran-3yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin-3(4H)-one (31c). The compound 31c was obtained in 61% yield from the compounds 31b and 32 according to the general procedure B. Beige foam; 1H NMR δ (DMSO-d6): 10.84 (s, 1 H), 8.70 (d, J = 4.6 Hz, 1 H), 8.23 (d, J = 9.1 Hz, 1 H), 7.80 (d, J = 4.7 Hz, 1 H), 7.73 (d, J = 7.9 Hz, 1 H), 7.51 (d, J = 16.3 Hz, 1 H), 7.26 (d, J = 9.1 Hz, 1 H), 7.09 (d, J = 7.9 Hz, 1 H), 6.91 (dd, J = 5.2, 16.4 Hz, 1 H), 3.99-4.08 (overlaid m, 2H), 4.03 (s, 3H), 3.69-3.80 (br s, 2H), 3.51 (s, 2H), 3.10 (t, J = 10.5 Hz, 1 H), 2.56 (m, overlaid with DMSO, 1H), 2.022.16 (m, 2H), 1.87 (m, 1H), 1.28-1.50 (m, 2H);13C NMR δ (CDCl3): 165.7, 161.5, 157.0, 148.3, 147.6, 142.3, 140.7, 140.3, 139.3, 136.2, 135.9, 124.4, 119.5, 117.8, 116.4, 113.6, 78.0, 72.5, 53.8, 53.2, 51.6, 31.2, 31.0, 29.7; HR ESI-MS (M+H)+ m/z =464.1759 (calc. for C24H26N5O3S: 464.1756); tR = 1.29.
(3R,6S)-N-((2,3-dihydro-[1,4]dioxino[2,3-c]pyridin-7-yl)methyl)-6-((E)-2-(6-methoxy1,5-naphthyridin-4-yl)vinyl)tetrahydro-2H-pyran-3-amine (31d). The compound 31d was obtained in 73% yield from the compounds 31b and 33 according to the general procedure B. Colorless foam; 1H NMR δ (DMSO-d6): 8.69 (d, J = 4.6 Hz, 1H), 8.22 (d, J = 9.0 Hz, 1H), 8.00 (s,
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1H), 7.80 (d, J = 4.7 Hz, 1H), 7.50 (dd, J = 0.9, 16.6 Hz, 1H), 7.25 (d, J = 9.1 Hz, 1H), 6.93 (s, 1H), 6.90 (overlaid dd, J = 5.3, 16.6 Hz, 1H), 4.30-4.34 (m, 2H), 4.23-4.28 (m, 2H), 3.96-4.05 (overlaid m, 2H), 4.02 (s, 3H), 3.63-3.73 (m, 2H), 3.08 (t, J = 10.4 Hz, 1H), 2.51 (m, overlaid with DMSO, 1H), 2.11 (br s, 1H), 2.02 (m, 1H), 1.85 (m, 1H), 1.28-1.47 (m, 2H); HR ESI-MS (M+H)+ m/z =435.2031 (calc. for C24H27N4O4: 435.2032); tR = 1.30.
tert-butyl
((3R,6R)-6-(2-(6-methoxy-1,5-naphthyridin-4-yl)ethyl)tetrahydro-2H-
pyran-3-yl)carbamate (34a). To a solution of 31a (0.975 g, 2.53 mmol) in MeOH (20 mL) was added 10% palladium on charcoal (0.5 g). The reaction was stirred under H2 for 90 min. After dilution with EtOAc (200 mL), the catalyst was removed by filtration and the filtrate was concentrated to dryness to afford 34a (0.97 g, 99% yield). Beige solid; m.p.= 152.5 °C; 1H NMR δ (DMSO-d6): 8.64 (d, J = 4.5 Hz, 1H), 8.22 (d, J = 9.0 Hz, 1H), 7.50 (d, J = 4.5 Hz, 1H), 7.22 (d, J = 9.0 Hz, 1H), 6.69 (br d, J = 7,9 Hz, 1H), 4.00 (s, 3H), 3.79 (m, 1H), 3.30 (overlaid m, 1H), 3.04-3.28 (m, 3H), 2.91 (t, J = 10.6 Hz, 1H), 1.79-1.89 (m, 3H), 1.71 (m, 1H), 1.35 (s, 9H), 1.21-1.37 8m, 2H);
13
C NMR δ
(CDCl3): 161.3, 155.2, 148.3, 147.7, 141.5, 141.0, 140.3, 123.9, 116.2, 79.5, 77.3, 76.5, 53.6, 46.6, 35.4, 30.7, 30.6, 28.4 (3C), 27.0; HR ESI-MS (M+H)+ m/z = 388.2239 (calc. for C21H30N3O4: 388.2236); tR = 1.23.
(3R,6R)-6-(2-(6-methoxy-1,5-naphthyridin-4-yl)ethyl)tetrahydro-2H-pyran-3-amine (34b). The compound 34b was prepared in 84% yield from the compound 34a according to the general procedure A. White solid; 1H NMR δ (CDCl3): 8.66 (d, J = 7.5 Hz, 1H), 8.20 (d, J = 9.0 Hz, 1H), 7.40 (d, J = 7.5 Hz, 1H), 7.11 (d, J = 9.0 Hz, 1H), 4.09 (s, 3H), 4.00 (ddd, J = 2.2, 4.4, 10.6 Hz, 1H), 3.34-3.17 (m, 3H), 3.02 (t, J = 10.6 Hz, 1H), 2.86 (m, 1H), 2.08-1.92 (m, 3H), 1.74 (m, 1H), 1.62 (br s, 2H), 1.46 (m, 1H), 1.26 (m, 1H); ESI-MS (M+H)+ m/z = 288.3.
6-((((3R,6R)-6-(2-(6-methoxy-1,5-naphthyridin-4-yl)ethyl)tetrahydro-2H-pyran-3yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin-3(4H)-one (34c). The compound 34c was obtained in 27% yield from the compounds 34b and 32 according to the general procedure B. White foam; 1H NMR δ (DMSO-d6): 10.87 (s, 1H), 8.66 (d, J = 4.4 Hz, 1H), 8.23 (d, J = 9.0 Hz, 1H), 7.73
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(d, J = 7.8 Hz, 1H), 7.52 (d, J = 4.4 Hz, 1H), 7.24 (d, J = 9.0 Hz, 1H), 7.08 (d, J = 7.8 Hz, 1H), 4.06 (s, 3H), 3.95 (ddd, J = 1.6, 4.4, 12.5 Hz, 1H), 3.72 (br s, 2H), 3.53 (s, 2H), 3.21-3.09 (m, 3H), 2.93 (t, J = 10.4 Hz, 1H), 2.48 (m, overlaid with DMSO, 1H), 2.09 (br s, 1H), 1.99 (m, 1H), 1.84 (m, 2H), 1.73 (m, 1H), 1.28-1.15 (m, 2H); HR ESI-MS (M+H)+ m/z =466.1915 (calc. for C24H28N5O3S: 466.1912) ; t
R = 1.30.
(3R,6R)-N-((2,3-dihydro-[1,4]dioxino[2,3-c]pyridin-7-yl)methyl)-6-(2-(6-methoxy-1,5naphthyridin-4-yl)ethyl)tetrahydro-2H-pyran-3-amine (34d). The compound 34d was obtained in 50% yield from the compounds 34b and 33 according to the general procedure B. Colorless oil; 1H NMR δ (DMSO-d6): 8.64 (d, J = 4.4 Hz, 1 H), 8.21 (d, J = 9.0 Hz, 1 H), 7.98 (s, 1 H), 7.49 (d, J = 4.5 Hz, 1 H), 7.22 (d, J = 9.0 Hz, 1 H), 6.90 (s, 1 H), 4.29-4.33 (m, 2H), 4.23-4.27 (m, 1H), 3.99 (s, 3H), 3.90 (m, 1H), 3.59-3.69 (m, 2H), 3.04-3.29 (m, 3H), 2.89 (t, J = 10.4 Hz, 1H), 2.41 (m, 1H), 2.00 (br s, 1H), 1.93 (m, 1H), 1.74-1.89 (m, 2H), 1.68 (m, 1H), 1.07-1.29 (m, 2H); HR ESIMS (M+H)+ m/z =437.2188 (calc. for C24H29N4O4: 437.2189); tR = 1.31.
General Procedure D: Asymmetric dihydroxylation using AD-mix-α α or-β β To a mixture of alkene (1eq) in t-BuOH (4 mL/mmol), EtOAc (1 mL/mmol) and water (5 mL/mmol) were added AD-mix-β or AD-mix-α (1.4 g /mmol) and CH3SO2NH2 (1.1eq). The reaction mixture was stirred vigorously until completion. NaHSO3 (1.5g/mmol) was added carefully and the mixture was stirred 30 min. EtOAc (10 mL/mmol) was added and the two layers were decanted. The aq. layer was extracted with EtOAc (2 x 10 mL/mmol). The combined extracts were washed with brine, dried over Na2SO4, filtered and concentrated to dryness. The residue was purified by chromatography (DCM-MeOH with an appropriate gradient).
tert-butyl
((3R,6S)-6-((1S,2R)-1,2-dihydroxy-2-(6-methoxy-1,5-naphthyridin-4-
yl)ethyl)tetrahydro-2H-pyran-3-yl)carbamate (35a). The compound 35a was prepared in 92% yield from 31a according to the general procedure D (AD-mix-β). White solid; m.p.= 114.9 °C; 1H NMR (d6-DMSO) δ: 8.76 (d, J = 4.5 Hz, 1H), 8.25 (d, J = 9.0 Hz, 1H), 7.74 (d, J = 4.5 Hz, 1H), 7.25 (d, J = 9.0 Hz, 1H), 6.81 (br s, 1H), 6.75 (d, J = 7.8 Hz, 1H), 5.65 (br d, J = 6.6 Hz, 1H), 5.28 (d, J =
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6.8 Hz, 1H), 4.41 (d, J = 6.4 Hz, 1H), 4.00 (s, 3H), 3.79 (m, 2H), 3.33 (m, 1H), 2.92 (t, J = 10.7 Hz, 1H), 1.96 (m, 2H), 1.47 (m, 2H), 1.38 (s, 9H); 13C NMR δ (CDCl3): 161.2, 155.1, 147.7, 146.6, 141.2, 140.5, 139.2, 122.2, 116.5, 79.6, 78.5, 75.1, 71.5, 71.3, 53.9, 46.3, 30.0, 28.3 (3C), 26.8; HR ESI-MS (M+H)+ m/z = 420.2132 (calc. for C21H30N3O6: 420.2134); tR = 0.97.
tert-butyl
((3S,6R)-6-((1R,2S)-1,2-dihydroxy-2-(6-methoxy-1,5-naphthyridin-4-
yl)ethyl)tetrahydro-2H-pyran-3-yl)carbamate (ent-35a). Compound ent-35a was prepared in 88% yield from compound ent-31a using the general procedure D (AD-mix-α). Colorless solid; 1H NMR was identical to 35a. ESI-MS (M+H)+ m/z = 464.1.
(1S,2R)-1-((2S,5R)-5-aminotetrahydro-2H-pyran-2-yl)-2-(6-methoxy-1,5naphthyridin-4-yl)ethane-1,2-diol (35b). The compound 35b was obtained in 80% yield from the compound 35a according to the general procedure A. Yellowish foam; 1H NMR δ (CDCl3): 8.78 (d, J = 4.5 Hz, 1H), 8.25 (d, J = 9.3 Hz, 1H), 7.56 (d, J = 4.5 Hz, 1H), 7.14 (d, J = 9.0 Hz, 1H), 5.59 (d, J = 3.3 Hz, 1H), 4.04 (s, 3H), 3.98 (partially overlaid m, 2H), 3.38 (br d, J = 11.4 Hz, 1H), 3.01 (t, J = 10.8 Hz, 1H), 2.86 (m, 1H), 2.08 (m, 1H), 1.85 (m, 1H), 1.63 (m, 1H), 1.28 (br s, 4H), 1.26 (overlaid m, 1H); ESI-MS (M+H)+ m/z = 320.2.
(1R,2S)-1-((2R,5S)-5-aminotetrahydro-2H-pyran-2-yl)-2-(6-methoxy-1,5naphthyridin-4-yl)ethane-1,2-diol (ent-35b). The compound ent-35b was prepared in 92% yield from the compound ent-35a according to the general procedure A. Colorless foam; 1H NMR was identical to 35a; ESI-MS (M+H)+ m/z = 320.2.
6-((((3R,6S)-6-((1S,2R)-1,2-dihydroxy-2-(6-methoxy-1,5-naphthyridin-4yl)ethyl)tetrahydro-2H-pyran-3-yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin-3(4H)one (35c). The compound 35c was obtained in 27% yield from the compounds 35b and 32 according to the general procedure B. White solid; 1H NMR δ (DMSO-d6): 10.84 (s, 1H), 8.73 (d, J = 4.6 Hz, 1H), 8.23 (d, J = 9.1 Hz, 1H), 7.67-7.75 (m, 2H), 7.22 (d, J = 9.1 Hz, 1H), 7.07 (d, J = 7.8 Hz, 1H), 5.63 (m, 1H), 5.23 (d J = 6.7 Hz, 1H), 4.33 (d, J = 6.2 Hz, 1H), 3.95 (s, 3H), 3.92 (overlaid m, 1H), 3.67-3.76 (m, 3H), 3.50 (s, 2H), 3.33 (overlaid m, 1H), 2.90 (t, J = 10.6 Hz, 1H), 2.50 (m, overlaid
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with DMSO, 1H), 2.08 (m, 1H), 1.93 (m, 1H), 1.44 (m, 1H), 1.22-1.33 (m, 2H); HR ESI-MS (M+H)+ m/z =498.1808 (calc. for C24H28N5O5S: 498.1811); tR = 1.01.
6-((((3S,6R)-6-((1R,2S)-1,2-dihydroxy-2-(6-methoxy-1,5-naphthyridin-4yl)ethyl)tetrahydro-2H-pyran-3-yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin-3(4H)one (ent-35c). The compound ent-35c was obtained in 32% yield from the compounds ent-35b and 32 according to the general procedure B. Beige foam; 1H NMR was identical to 35c. HR ESI-MS (M+H)+ m/z =498:1815 (calc. for C24H28N5O5S: 498.1811); tR = 1.01.
(1S,2R)-1-((2S,5R)-5-(((2,3-dihydro-[1,4]dioxino[2,3-c]pyridin-7yl)methyl)amino)tetrahydro-2H-pyran-2-yl)-2-(6-methoxy-1,5-naphthyridin-4yl)ethane-1,2-diol (35d). The compound 35d was obtained in 38% yield from the compounds 35b and 33 according to the general procedure B. White foam; 1H NMR δ (DMSO-d6): 8.73 (d, J = 4.5 Hz, 1 H), 8.23 (d, J = 9.1 Hz, 1 H), 7.99 (s, 1 H), 7.72 (d, J = 4.5 Hz, 1 H), 7.22 (d, J = 9.1 Hz, 1 H), 6.91 (s, 1 H), 5.64 (m, 1H), 5.21 (d, J = 6.7 Hz, 1H), 4.29-4.34 (m, 3H), 4.23-4.27 (m, 2H), 3.95 (s, 3H), 3.87-3.94 (m, 1H), 3.60-3.74 (m, 3H), 3.35 (m, 1H), 2.87 (t, J = 10.4 Hz, 1H), 2.45 (m, overlaid with DMSO, 1H), 1.99-2.11 (m, 2H), 1.91 (m, 1H), 1.46 (m, 1H), 1.22 (m, 1H); HR ESI-MS (M+H)+ m/z =469.2095 (calc. for C24H29N4O6: 469.2087) ; tR = 0.97.
tert-butyl
((3R,6S)-6-((1R,2S)-1,2-dihydroxy-2-(6-methoxy-1,5-naphthyridin-4-
yl)ethyl)tetrahydro-2H-pyran-3-yl)carbamate (36a). The compound 36a was obtained in 98% yield from 31a using the general procedure D (AD-mix-α). White foam; 1H NMR (d6-DMSO) δ: 8.75 (d, J = 4.5 Hz, 1H), 8.24 (d, J = 9.0 Hz, 1H), 7.74 (d, J = 4.5 Hz, 1H), 7.23 (d, J = 9.0 Hz, 1H), 6.81 (br s, 1H), 6.75 (br d, J = 8.3 Hz, 1H), 5.83 (d, J = 6.1 Hz, 1H), 5.25 (d, J = 6.6 Hz, 1H), 4.49 (d, J = 8.1 Hz, 1H), 4.00 (s, 3H), 3.76 (m, 1H), 3.67 (app t, J = 6.6 Hz, 1H), 3.36 (m, 1H), 2.99 (t, J = 10.9 Hz, 1H), 1.99-1.86 (m, 2H), 1.38 (s, 9H), 1.35-1.13 (m, 2H); ESI-MS (M+H)+ m/z = 420.2.
tert-butyl
((3S,6R)-6-((1S,2R)-1,2-dihydroxy-2-(6-methoxy-1,5-naphthyridin-4-
yl)ethyl)tetrahydro-2H-pyran-3-yl)carbamate (ent-36a). Compound ent-36a was prepared in
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54% yield from compound ent-31a using the general procedure D (AD-mix-β ). Colorless solid; 1H NMR was identical to 36a. ESI-MS (M+H)+ m/z = 464.1.
(1R,2S)-1-((2S,5R)-5-aminotetrahydro-2H-pyran-2-yl)-2-(6-methoxy-1,5naphthyridin-4-yl)ethane-1,2-diol (36b). The compound 36b was obtained in 47% yield from the compound 36a (0.47 g, 2.08 mmol) according to the general procedure A. Yellowish foam; 1H NMR δ (DMSO-d6): 8.75 (d, J = 4.5 Hz, 1H), 8.24 (d, J = 9.0 Hz, 1H), 7.74 (d, J = 4.5 Hz, 1H), 7.23 (d, J = 9.0 Hz, 1H), 5.84 (d, J = 5.3 Hz, 1H), 5.21 (d, J = 6.5 Hz, 1H), 4.46 (d, J = 8.3 Hz, 1H), 3.99 (s, 3H), 3.76 (ddd, J = 2.5, 4.6, 8.8 Hz, 1H), 3.65 (td, J = 1.5, 8.0 Hz, 1H), 3.32 (m, 1H), 2.86 (t, J = 10.4 Hz, 1H), 2.54 (m, overlaid with DMSO, 1H), 1.93 (m, 2H), 1.55, br s, 2H), 1.2-1.09 (m, 2H); ESI-MS (M+H)+ m/z = 320.2.
(1S,2R)-1-((2R,5S)-5-aminotetrahydro-2H-pyran-2-yl)-2-(6-methoxy-1,5naphthyridin-4-yl)ethane-1,2-diol (ent-36b). The compound ent-36b was prepared in 64% yield from the compound ent-36a according to the general procedure A. Colorless foam; 1H NMR was identical to 36a; ESI-MS (M+H)+ m/z = 320.2.
6-((((3R,6S)-6-((1R,2S)-1,2-dihydroxy-2-(6-methoxy-1,5-naphthyridin-4yl)ethyl)tetrahydro-2H-pyran-3-yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin-3(4H)one (36c). The compound 36c was obtained in 22% yield from the compounds 36b and 32 according to the general procedure B. White solid; 1H NMR δ (DMSO-d6): 10.84 (s, 1H), 8.71 (d, J = 4.6 Hz, 1H), 8.22 (d, J = 9.1 Hz, 1H), 7.66-7.78 (m, 2H), 7.20 (d, J = 9.1 Hz, 1H), 7.06 (d, J = 7.8 Hz, 1H), 5.79 (m, 1H), 5.19 (d J = 5.4 Hz, 1H), 4.44 (d, J = 6.2 Hz, 1H), 3.94 (s, 3H), 3.89 (overlaid m, 1H), 3.72 (br s, 2H), 3.61 (m, 1H), 3.50 (s, 2H), 3.32 (overlaid m, 1H), 2.95 (t, J = 10.6 Hz, 1H), 2.50 (overlaid with DMSO , m, 1H), 2.02 (m, 1H), 1.92 (m, 1H), 1.02-1.28 (m, 3H); HR ESI-MS (M+H)+ m/z =498.1806 (calc. for C24H28N5O5S: 498.1811); tR = 1.01.
6-((((3S,6R)-6-((1S,2R)-1,2-dihydroxy-2-(6-methoxy-1,5-naphthyridin-4yl)ethyl)tetrahydro-2H-pyran-3-yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin-3(4H)one (ent-36c). The compound ent-36c was prepared in 60% yield from the compounds ent-36b and
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32 according to the general procedure B. Beige foam; 1H NMR was identical to 36c; HR ESI-MS (M+H)+ m/z =498:1813 (calc. for C24H28N5O5S: 498.1811); tR = 1.01.
tert-butyl
((3R,6S)-6-((E)-2-(2-methoxyquinolin-8-yl)vinyl)tetrahydro-2H-pyran-3-
yl)carbamate (37). The compound 37 was prepared in 30% yield from the compounds 18 and 26b according to the general procedure C (KHMDS). White solid m.p.= 62.9°C; 1H NMR (DMSO-d6) δ: 8.23 (d, J = 8.9 Hz, 1H), 7.90 (d, J = 6.5 Hz, 1H), 7.79 (d, J = 8.0 Hz, 1H), 7.61 (d, J = 16.0 Hz, 1H), 7.40 (dd, J = 6.5, 8.0 Hz, 1H), 7.03 (d, J = 8.9 Hz, 1H), 6.83 (d, J = 7.8 Hz, 1H), 6.58 (dd, J = 5.9, 16.0 Hz, 1H), 4.02 (s, 3H), 3.99 (m, 1H), 3.88 (dd, J = 3.4, 10.7 Hz, 1H), 3.40 (br s, 1H), 3.09 (t, J = 10.5 Hz, 1H), 1.88 (m, 2H), 1.51 (m, 2H); ESI-MS (M+H)+ m/z = 385.3.
tert-butyl
((3R,6S)-6-((E)-2-(3-methoxyquinolin-5-yl)vinyl)tetrahydro-2H-pyran-3-
yl)carbamate (38). The compound 38 was obtained in 42% yield from 19b and 18 using the general procedure C (LiHMDS). Off-white solid; 1H NMR δ (DMSO-d6): 8.64 (d, J = 2.8 Hz, 1H), 7.87 (d, J = 8.1 Hz, 1H), 7.81 (d, J = 2.8 Hz, 1H), 7.72 (d, J = 6.6 Hz, 1H), 7.53 (dd, J = 6.6, 8.1 Hz, 1H), 7.36 (d, J = 15.7 Hz, 1H), 6.82 (d, J = 8.1 Hz, 1H), 6.32 (dd, J = 6.2, 15.7 Hz, 1H), 4.00 (m, 1H), 3.97 (s, 3H), 3.88 (m, 1H), 3.38 (br s, 1H), 3.08 (t, J = 10.7 Hz, 1H), 1.88 (m, 2H), 1.51 (m, 2H), 1.38 (s, 9H); ESI-MS (M+H)+ m/z = 385.0.
tert-butyl
((3R,6S)-6-((E)-2-(3-fluoro-6-methoxyquinolin-4-yl)vinyl)tetrahydro-2H-
pyran-3-yl)carbamate (39). The compound 39 was obtained in 39% yield from 20b and 18 using the general procedure C (LiHMDS). Off-white solid; 1H NMR δ (CDCl3): 8.70 (d, J = 2.2 Hz, 1 H), 7.93 (d, J = 9.8 Hz, 1 H), 7.38 (d, J = 5.5Hz, 1H), 6.98 (dd, J = 1.3, 16.4 Hz, 1 H), 6.80 (d, J = 3.2 Hz, 1H), 6.50 (dd, J= 5.3, 16.4 Hz, 1 H), 4.05 (m, 1H), 3.97 (s, 3H), 3.89 (m, 1H), 3.38 (br s, 1H), 3.09 (t, J = 10.7 Hz, 1H), 1.88 (m, 2H), 1.51 (m, 2H), 1.38 (s, 9H); ESI-MS (M+H)+ m/z = 403.2.
tert-butyl ((3R,6S)-6-((E)-2-(6-fluoro-3-methoxyquinoxalin-5-yl)vinyl)tetrahydro-2Hpyran-3-yl)carbamate (40). Starting from 18 (25.4 g, 60 mmol) and 21b (12.4 g, 60 mmol), 40 (16.6 g, 52%) was prepared using the general procedure C (LiHMDS). White solid; 1H NMR δ (DMSO-d6): 8.59 (s, 1 H), 7.93 (dd, J = 5.8, 9.1 Hz, 1 H), 7.54 (dd, J = 9.2, 11.0 Hz, 1 H), 7.23 (dd, J
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= 0.6, 16.4 Hz, 1 H), 6.88 (dd, J = 5.3, 16.5 Hz, 1 H), 6.79 (d, J = 7.3 Hz, 1 H), 4.05 (s, 3H), 3.84-4.00 (m, 2H), 3.38 (m, 1H), 3.08 (t, J = 10.6 Hz, 1H), 1.81-1.94 (m, 2H), 1.40-1.53 (m, 2H), 1.36 (s, 9H); MS (ESI): m/z 404.4 (M+H)+.
tert-butyl
((3R,6S)-6-((E)-2-(3-fluoro-6-methoxy-1,5-naphthyridin-4-
yl)vinyl)tetrahydro-2H-pyran-3-yl)carbamate (41). The compound 41 was prepared in 68% yield starting from 18 and 24b using the general procedure C (LiHMDS). White solid; m.p.= 179.4 °C; 1
H NMR δ (DMSO-d6): 8.79 (d, J = 2.2 Hz, 1H), 8.26 (d, J = 9.1 Hz, 1H), 7.28 (d, J = 17 Hz, 1H),
7.24 (d, J = 9.1 Hz, 1H), 7.17 (dd, J = 4.5, 17 Hz, 1H), 6.81 (m, 1H), 4.02 (s, 3H), 4.01 (m, 1H), 3.91 (m, 1H), 3.09 (t, J = 10.6 Hz, 1H), 1.91 (d, J = 9.6 Hz, 2H), 1.35-1.58 (overlaid m, 1H), 1.38 (s, 9H); HR ESI-MS (M+H)+ m/z = 404.1988 (calc. for C21H27N3O4F: 404.1985) ; tR = 1.44.
tert-butyl
((3R,6S)-6-((E)-2-(8-fluoro-6-methoxyquinolin-4-yl)vinyl)tetrahydro-2H-
pyran-3-yl)carbamate (42). The compound 42 was prepared in 74% yield from 18 and 25b according to the general procedure A. Yellowish solid; ESI-MS (M+H)+ m/z = 403.0.
tert-butyl
((3R,6S)-6-((E)-2-(6-methoxyquinolin-4-yl)vinyl)tetrahydro-2H-pyran-3-
yl)carbamate (43). The compound 43 was prepared in 41% yield from 18 and 22b using the general procedure A (KHMDS). Yellowish foam;. 1H NMR (CDCl3) δ: 8.69 (d, J = 4.6 Hz, 1H), 8.03 (d, J = 9.2 Hz, 1H), 7.28-7.42 (m, 3H), 7.25 (d, J = 15.8 Hz, 1H), 6.42 (dd, J = 5.2, 15.8 Hz, 1H), 4.33 (br s, 1H), 4.23 (ddd, J = 2.0, 4.7, 10.6 Hz, 1H), 4.05 (m, 1H), 3.96 (s, 3H), 3.70 (br s, 1H), 3.16 (t, J = 10.6 Hz, 1H), 2.18 (m, 1H), 1.95 (m, 1H), 1.65 (m, 1H), 1.45 (overlaid m, 1H), 1.45 (s, 9H); ESI-MS (M+H)+ m/z = 385.3.
tert-butyl
((3R,6S)-6-((1S,2R)-1,2-dihydroxy-2-(2-methoxyquinolin-8-
tert-butyl
((3R,6S)-6-((E)-2-(3-methoxyquinoxalin-5-yl)vinyl)tetrahydro-2H-pyran-3-yl)carbamate (44). The compound 44 was prepared in 57% yield from 27b and 18 (3.81 g, 9 mmol) using the general procedure A (LiHMDS). Beige solid; 1H NMR δ (DMSO-d6): 8.62 (s, 1H), 7.99 (d, J = 7.4 Hz, 1H), 7.91 (dd, J = 1.2, 8.2 Hz, 1H), 7.60 (dd, J = 7.4, 8.2 Hz, 1H), 7.53 (d, J = 15.8 Hz, 1H), 6.84 (d, J = 8.0 Hz, 1H), 6.63 (dd, J = 5.7, 15.8 Hz, 1H), 4.08 (s, 3H), 3.99 (m, 1H), 3.89 (br dd, J = 3.0,
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Journal of Medicinal Chemistry
10.2 Hz, 1H), 3.38 (br s, 1H), 3.09 (t, J = 10.5 Hz, 1H), 1.91-1.86 (m, 2H), 1.53-1.45 (m, 2H), 1.39 (s, 9H) ESI-MS (M+H)+ m/z = 386.2.
tert-butyl
((3R,6S)-6-((1S,2R)-1,2-dihydroxy-2-(2-methoxyquinolin-8-
yl)ethyl)tetrahydro-2H-pyran-3-yl)carbamate (45a). The compound 45a was prepared in 92% yield from 37 following the general procedure D (AD mix β). 1H NMR δ (DMSO-d6): 8.20 (d, J = 8.9Hz, 1H), 7.69-7.78 (m, 2H), 7.39 (t, J = 7.6 Hz, 1H), 6.98 (d, J = 8.9 Hz, 1H), 6.77 (br s, 1H), 6.68 (m, 1H), 5.65 (m, 1H), 5.00 (d, J = 6.7 Hz, 1H), 4.19 (d, J = 6.3 Hz, 1H), 3.95 (s, 3H), 3.78 (m, 1H), 3.67 (m, 1H), 3.22 (m, 1H), 2.79 (t, J = 10.8 Hz, 1H), 1.81-1.96 (m, 2H), 1.53 (m, 1H), 1.37 (s, 9H), 1.35 (overlaid m, 1H); HR ESI-MS (M+H)+ m/z =419.2178 (calc. for C22H31N2O6: 419.2182); tR = 1.35.
(1S,2R)-1-((2S,5R)-5-aminotetrahydro-2H-pyran-2-yl)-2-(3-methoxyquinolin-5yl)ethane-1,2-diol (46a). The compound 46a was obtained in 86% yield from the compound 38 following the general procedure D (AD mix β). White foam; 1H NMR δ (CDCl3): 8.69 (d, J = 2.4 Hz, 1H), 8.04 (d, J = 8.4 Hz, 1H), 7.82 (d, J = 2.4 Hz, 1H), 7.72 (d, J = 6.3 Hz, 1H), 7.58 (dd, J = 6.3, 8.1 Hz, 1H), 5.44 (d, J = 6.9 Hz, 1H), 4.82 (br s, 2H), 4.13 (m, 2H), 3.96 (s, 3H), 3.67 (d, J = 6 Hz, 1H), 3.59 (br s, 1H), 2.94 (m, 1H), 2.79 (t, J = 10.8 Hz, 1H), 2.02 (m, 1H), 1.88 (qd, J = 4.2, 11.7 Hz, 1H), 1.50 (partially overlaid m, 1H), 1.43 (s, 9H), 1.15 (qd, J = 5.1, 12.6 Hz, 1H); ESI-MS (M+H)+ m/z = 419.2.
tert-butyl
((3R,6S)-6-((1S,2R)-2-(3-fluoro-6-methoxyquinolin-4-yl)-1,2-
dihydroxyethyl)tetrahydro-2H-pyran-3-yl)carbamate (47a). The compound 47a was prepared in 82% yield from 39 following the general procedure D (AD mix β). 1H NMR δ (DMSOd6): 8.65 (d, J = 1.5 Hz, 1 H), 7.91 (d, J = 9.2 Hz, 1 H), 7.79 (d, J = 2.3 Hz, 1 H) 7.35 (m, 1 H), 6.51 (m, 1 H), 5.68 (d, J = 4.4 Hz, 1 H), 5.38 (m, 1 H), 5.04 (d, J = 6.0 Hz, 1 H), 3.85 (overlaid m, 1H), 3.85 (s, 3H), 3.66 (m, 1H), 3.25 (m, 1H), 2.62 (m, 1H), 2.43 (m, overlaid with DMSO, 1H), 1.74 (m, 1H), 1.63 (m, 1H), 1.39 (overlaid m, 1H), 1.37 (s, 9H), 1.11 (m, 1H); ESI-MS (M+H)+ m/z = 437.2.2.
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tert-butyl
((3R,6S)-6-((1S,2R)-2-(6-fluoro-3-methoxyquinoxalin-5-yl)-1,2-
dihydroxyethyl)tetrahydro-2H-pyran-3-yl)carbamate (48a). Starting from 40 (10.6 g, 26.4 mmol), 48a (10.26 g, 89%) was prepared following the general procedure D (AD-mix-β ). White foam; 1
H NMR δ (DMSO-d6): 8.57 (s, 1 H), 7.96 (dd, J = 5.6, 9.1 Hz, 1 H), 7.47 (dd, J = 9.2, 10.3 Hz, 1 H),
6.49 (m, 1 H), 5.65 (t, J = 6.9 Hz, 1 H), 5.12 (d, J = 6.9 Hz, 1 H), 4.75 (d, J = 6.0 Hz, 1 H), 4.03 (s, 3H), 3.92 (m, 1H), 3.60 (m, 1H), 3.19 (br s, 1H), 2.76 (m, 1H), 2.50 (m, overlaid with DMSO, 1H), 1.71-1.84 (m, 1H), 1.43-1.68 (m, 2H), 1.33 (s, 9H), 1.07-1.22 (m, 1H); MS (ESI): m/z 438.4 (M+H)+.
tert-butyl
((3R,6S)-6-((1S,2R)-2-(3-fluoro-6-methoxy-1,5-naphthyridin-4-yl)-1,2-
dihydroxyethyl)tetrahydro-2H-pyran-3-yl)carbamate (49a). The compound 49a was prepared in 77% yield starting from 41 and applying the general procedure D (AD-mix-β ). Yellowish solid; m.p.= 80.6 °C; 1H NMR δ (DMSO-d6): 8.76 (s, 1H), 8.29 (d, J = 9.1 Hz, 1H), 6.81 (br s, 1H), 6.59 (d, J = 7.9 Hz, 1H), 5.72 (t, J = 6.2 Hz, 1H), 5.47 (d, J = 7.0 Hz, 1H), 4.88 (d, J = 5.9 Hz, 1H), 4.02 (s, 3H), 3.89 (m, 1H), 3.63 (m, 1H), 3.23 (m, 1H), 2.94 (m, 1H), 2.61 (t, J = 10.6 Hz, 1H), 1.82 (m, 1H), 1.56-1.70 (m, 2H), 1.35 (s, 9H), 1.12-1.27 (m, 1H); HR ESI-MS (M+H)+ m/z = 438.2043 (calc. for C21H29N3O6F: 438.2040) ; tR = 1.10.
tert-butyl
((3R,6S)-6-((1S,2R)-2-(8-fluoro-6-methoxyquinolin-4-yl)-1,2-
dihydroxyethyl)tetrahydro-2H-pyran-3-yl)carbamate (50a). The compound 50a was prepared in 79% yield from the compound 42 applying the general procedure D (AD mix β). Brown oil; ESI-MS (M+H)+ m/z = 437.3.
tert-butyl
((3R,6S)-6-((1S,2R)-1,2-dihydroxy-2-(6-methoxyquinolin-4-
yl)ethyl)tetrahydro-2H-pyran-3-yl)carbamate (51a). The compound 51a was prepared in 38% yield, starting from 43 and using the general procedure D (AD mix β). White foam; 1H NMR (CDCl3)
δ: 8.72 (d, J = 4.5 Hz, 1H), 8.03 (d, J = 9.2 Hz, 1H), 7.57 (d, J = 4.5 Hz, 1H), 7.38 (dd, J = 2.7, 9.2 Hz, 1H), 7.32 (d, J = 2.7 Hz, 1H), 5.51 (d, J = 5.3 Hz, 1H), 4.21 (br d, partially overlaid, J = 6.2 Hz, 1H), 4.18 (ddd, J = 1.8, 4.6, 10.5 Hz, 1H), 3.94 (s, 3H), 3.69 (dd, J = 2.6, 5.2 Hz, 1H), 3.63 (br s, 1H), 3.15
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(td, J = 2.2, 11.4 Hz, 1H), 2.91 (t, J = 10.6 Hz, 1H), 2.07 (m, 1H), 1.91 (qd, J = 4.0, 13.4 Hz, 1H), 1.90 (br s, 2H), 1.62 (m, 1H), 1.45 (s, 9H), 1.19 (qd, J = 4.2, 12.5 Hz, 1H); ESI-MS (M+H)+ m/z = 419.4.
tert-butyl
((3R,6S)-6-((1S,2R)-1,2-dihydroxy-2-(3-methoxyquinoxalin-5-
yl)ethyl)tetrahydro-2H-pyran-3-yl)carbamate (52a). The compound 52a was prepared in 86% yield starting from 44 using the general procedure D (AD-mix-β ) White foam; ESI-MS (M+H)+ m/z = 420.1.
(1S,2R)-1-((2S,5R)-5-aminotetrahydro-2H-pyran-2-yl)-2-(2-methoxyquinolin-8yl)ethane-1,2-diol (45b). The compound 45b was prepared in 85% yield from the compound 45a using the general procedure A. Colorless solid; ESI-MS (M+H)+ m/z = 319.2.
(1S,2R)-1-((2S,5R)-5-aminotetrahydro-2H-pyran-2-yl)-2-(3-methoxyquinolin-5yl)ethane-1,2-diol (46b). The compound 46b was prepared in 63% yield from the compound 46a following the general procedure A. White foam; MS (ESI): m/z 319.2 (M+H)+.
(1S,2R)-1-((2S,5R)-5-aminotetrahydro-2H-pyran-2-yl)-2-(3-fluoro-6methoxyquinolin-4-yl)ethane-1,2-diol (47b). The compound 47b was prepared in 61% yield from the compound 47a following the general procedure A. White foam; 1H NMR δ (DMSO-d6): 8.64 (d, J = 1.7 Hz, 1 H), 7.91 (d, J = 9.2 Hz, 1 H), 7.79 (d, J = 2.4 Hz, 1 H), 7.35 (dd, J = 2.6, 9.2 Hz, 1 H), 5.65 (d, J = 4.4 Hz, 1 H), 5.38 (dd, J = 4.5, 7.5 Hz, 1 H), 4.97 (d, J = 5.9 Hz, 1 H), 3.87 (s, 3 H), 3.85 (overlaid m, 1H), 3.64 (m, 1 H), 2.58 (m, 1 H), 2.36 (m, 1 H), 1.76 (m, 1 H), 1.61 (m, 1 H), 1.32 (m, 1 H), 1.21 (br s, 2 H), 0.87 (m, 1H); MS (ESI): m/z 337.1.2 (M+H)+.
(1S,2R)-1-((2S,5R)-5-aminotetrahydro-2H-pyran-2-yl)-2-(6-fluoro-3methoxyquinoxalin-5-yl)ethane-1,2-diol (48b). Starting from 48a (0.546 g, 1.25 mmol), 48b (0.363 g, 86%) was prepared according to the general procedure A. White solid; m.p.= 65.6 °C; 1H NMR δ (DMSO-d6): 8.57 (s, 1 H), 7.96 (dd, J = 5.6, 9.1 Hz, 1 H), 7.47 (dd, J = 9.1, 10.4 Hz 1 H), 5.66 (t, J = 6.9 Hz, 1 H), 5.10 (d, J = 6.8 Hz, 1 H), 4.68 (d, J = 6.0 Hz, 1 H), 4.04 (s, 3H), 3.92 (m, 1H), 3.55 (m, 1H), 2.74 (m, 1H), 2.29-2.43 (m, 2H), 1.78 (m, 1H), 1.58 (m, 1H), 1.41 (m, 1H), 1.18
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(br s, 2H), 0.91 (m, 1H); 13C NMR δ (CDCl3): 160.6 (d, J = 251 Hz), 156.6, 139.9 (d, J = 9 Hz), 138.9 (d, J = 3 Hz), 136.1, 130.5 (d, J = 11 Hz), 121.1 (d, J = 15 Hz), 116.6 (d, J = 27 Hz), 76.9, 74.8, 69.5, 69.4, 54.3, 47.3, 33.4, 27.1; HR ESI-MS (M+H)+ m/z = 338.1521 (calc. for C16H21N3O4F: 338.1516); t
R = 0.57.
(1S,2R)-1-((2S,5R)-5-aminotetrahydro-2H-pyran-2-yl)-2-(3-fluoro-6-methoxy-1,5naphthyridin-4-yl)ethane-1,2-diol (49b). Starting from 49a, the compound 49b was prepared in 75% yield applying the general procedure A. White foam; 1H NMR δ (DMSO-d6): 8.73 (d, J = 1.9 Hz, 1 H), 8.27 (d, J = 9.1 Hz, 1 H), 7.22 (d, J = 9.1 Hz, 1 H), 5.69 (t, J = 6.6 Hz, 1 H), 5.41 (d, J = 7.1 Hz, 1 H), 4.78 (d, J = 6.0 Hz, 1 H), 4.01 (s, 3 H), 3.87 (m, 1 H), 3.56 (m, 1H), 2.90 (m, 1H), 2.32-2.50 (m, 2H), 1.80 (m, 1H), 1.51-1.6 (m, 2H), 1.16-1.31 (br s, 2H), 0.97 (m, 1H); HR ESI-MS (M+H)+ m/z = 338.1519 (calc. for C16H21N3O4F: 338.1516); tR = 0.57.
(1R,2R)-1-((2S,5R)-(5-amino-tetrahydro-pyran-2-yl)-2-(8-fluoro-6-methoxy-quinolin4-yl)-ethane-1,2-diol (50b). The compound 50b was prepared in 72% yield from intermediate 50a and applying the general procedure A. Yellowish solid; ESI-MS (M+H)+ m/z =337.2.
(1S,2R)-1-((2S,5R)-5-aminotetrahydro-2H-pyran-2-yl)-2-(6-methoxyquinolin-4yl)ethane-1,2-diol (51b). The compound 51b was obtained in quantitative yield from 51a using the general procedure A. White solid; ESI-MS (M+H)+ m/z = 319.1.
(1S,2R)-1-((2S,5R)-5-aminotetrahydro-2H-pyran-2-yl)-2-(3-methoxyquinoxalin-5yl)ethane-1,2-diol (52b). The compound 52b was prepared in 76% yield, starting from 52a and using the general procedure A. White foam; 1H NMR δ (DMSO-d6): 8.60 (s, 1H), 7.90-7.85 (m, 2H), 7.62 (dd, J = 7.7, 7.8 Hz, 1H), 5.68 (br s, 1H), 5.11 (br d, J = 4.3 Hz, 1H), 4.27 (br s, 1H), 4.03 (s, 3H), 3.77 (ddd, J = 1.7, 4.3, 10.4 Hz, 1H), 3.62 (dd, J = 2.3, 6.1 Hz, 1H), 3.23 (ddd, J = 1.7, 6.4, 11.0 Hz, 1H), 2.75 (t, J = 10.4 Hz, 1H), 2.56 (m, 1H), 1.95-1.84 (m, 2H), 1.52 (m, 1H), 1.45 (br s, 2H), 1.13 (m, 1H); ESI-MS (M+H)+ m/z = 320.2.
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Journal of Medicinal Chemistry
6-((((3R,6S)-6-((1S,2R)-1,2-dihydroxy-2-(2-methoxyquinolin-8-yl)ethyl)tetrahydro2H-pyran-3-yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin-3(4H)-one
(45c).
The
compound 45c was prepared in 35% yield from the compounds 45b and 32 using the general procedure B. Beige solid; 1H NMR δ (DMSO-d6): 10.87 (s, 1H), 8.21 (d, J = 9.0 Hz, 1H), 7-79-7.72 (m, 3H), 7.41 (app t, J = 7.6 Hz, 1H), 7.09 (d, J = 7.6 Hz, 1H), 7.00 (d, J = 8.8 Hz, 1H), 5.68 (dd, J = 2.6, 6.6 Hz, 1H), 5.02 (d, J = 6.6 Hz, 1H), 4.19 (d, J = 6.2 Hz, 1H), 3.96 (s, 3H), 3.95 (overlaid m, 1H), 3.74 (dd, AB system, J = 2.7, 15.0 Hz, 2H), 3.67 (td, J = 2.7, 6.4 Hz, 1H), 3.53 (s, 2H), 3.28 (m, 1H), 2.87 (t, J = 10.5 Hz, 1H), 2.07 (m, 2H), 1.89 (br d, J = 12.2 Hz, 1H), 1.49 (m, 1H), 1.30-1.11 (m, 3H); HR ESI-MS (M+H)+ m/z =497.1858 (calc. for C25H29N4O5S: 497.1858); tR = 1.35.
6-((((3R,6S)-6-((1S,2R)-1,2-dihydroxy-2-(3-methoxyquinolin-5-yl)ethyl)tetrahydro2H-pyran-3-yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin-3(4H)-one
(46c).
The
compound 46c was prepared in 10% yield from the compounds 46b and 32 using the general procedure B. Colorless foam; 1H NMR δ (DMSO-d6): 10.85 (s, 1H), 8.65(d, J = 2.8 Hz, 1H), 7.857.90 (m, 2H), 7.72 (d, J = 7.9 Hz, 1H), 7.64 (dd, J = 1.4, 7.3 Hz, 1H), 7.56 (dd, J = 7.3, 8.4 Hz, 1H), 7.06 (d, J = 7.9 Hz, 1H), 5.31 (m, 2H), 4.76 (d, J = 6.1 Hz, 1H), 3.99 (overlaid m, 1H), 3.98 (s, 3H), 3.91 (m, 1H), 3.65-3.75 (m, 2H), 3.51 (s, 2H), 3.49 (m, 1H), 2.70 (t, J = 10.6 Hz, 1H), 2.50 (m, overlaid with DMSO, 1H), 2.10 (br s, 1H), 1.99 (m, 1H), 1.93 (m, 1H), 1.55 (m, 1H), 1.19 (m, 1H); HR ESI-MS (M+H)+ m/z =497.1857 (calc. for C25H29N4O5S: 497.1858) ; tR = 0.95.
6-((((3R,6S)-6-((1S,2R)-2-(3-fluoro-6-methoxyquinolin-4-yl)-1,2dihydroxyethyl)tetrahydro-2H-pyran-3-yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin3(4H)-one (47c). The compound 47c was prepared in 39% yield from the compounds 47b and 32 using the general procedure B. Colorless foam; 1H NMR δ (DMSO-d6): 10.78 (s, 1 H), 8.63 (d, J = 1.6 Hz, 1 H), 7.90 (d, J = 9.2 Hz, 1 H), 7.78 (d, J= 2.3Hz , 1 H), 7.67 (d, J = 7.9 Hz, 1 H), 7.34 (dd, J = 2.2, 9.1 Hz, 1 H), 7.00 (d, J = 7.9 Hz, 1 H), 5.65 (d, J = 4.5 Hz, 1 H), 5.37 (m, 1 H), 4.97 (d, J = 6.0 Hz, 1 H), 3.85 (s, 3H), 3.85-3.73 (m, 2H), 3.58-3.68 (m, 2H), 3.49 (s, 2H), 3.49 (m, 1H), 2.66 (m, 1H), 2.45 (m, overlaid with DMSO, 1H), 1.84-2.00 (m, 2H), 1.58 (m, 1H), 1.35 (m, 1H), 0.95 (m, 1H); HR ESI-MS (M+H)+ m/z = 515.1765 (calc. for C25H28N4O5FS: 515.1764) ; tR = 1.06.
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6-((((3R,6S)-6-((1S,2R)-2-(6-fluoro-3-methoxyquinoxalin-5-yl)-1,2-dihydroxyethyl) tetrahydro-2H-pyran-3-yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin-3(4H)-one (48c). Starting from of 48b (0.063 g, 0.23 mmol) and 32 (0.037 g, 0.24 mmol), 48c (0.055 g, 57%) was prepared using general procedure B. Off-white foam; 1H NMR δ (DMSO-d6): 10.79 (s, 1 H), 8.55 (s, 1 H), 7.95 (dd, J = 5.6, 9.2 Hz, 1 H), 7.68 (d, J = 7.7 Hz, 1 H), 7.46 (app t, J = 9.9 Hz, 1 H), 6.99 (d, J = 7.8 Hz, 1 H), 5.64 (m, 1 H), 5.10 (d, J = 6.8 Hz, 1 H), 4.68 (d, J = 5.9 Hz, 1 H), 4.01 (s, 3H), 3.91 (m, 1H), 3.70 (m, 1H), 3.61 (br s, 2H), 3.50 (s, 2H), 2.77 (m, 1H), 2.44 (m, overlaid with DMSO, 1H), 2.29 (m, 1H), 1.84-2.01 (m, 2H), 1.40-1.65 (m, 2H), 0.97 (m, 1H); HR ESI-MS (M+H)+ m/z = 516.1710 (calc. for C24H27N5O5FS: 516.1717); tR = 1.13
6-((((3R,6S)-6-((1S,2R)-2-(3-fluoro-6-methoxy-1,5-naphthyridin-4-yl)-1,2dihydroxyethyl) tetrahydro-2H-pyran-3-yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin3(4H)-one (49c). The compound 49c was prepared in 32% yield from 49b and 32 and using the general procedure B. White solid; m.p.= 66.6 °C; 1H NMR δ (DMSO-d6): 10.83 (s, 1H), 8.75 (d, J = 1.5 Hz, 1H), 8.29 (d, J = 9.1 Hz, 1H), 7.68 (d, J = 7.8 Hz, 1H), 7.22 (d, J = 9.1 Hz, 1H), 7.02 (d, J = 7.8 Hz, 1H), 5.70 (br t, J = 7.1 Hz, 1H), 5.45 (d, J = 7.1 Hz, 1H), 4.83 (d, J = 6 Hz, 1H), 4.00 (s, 3H), 3.88 (m, 1H), 3.73 (m, 1H), 3.65 (br s, 2H), 3.53 (s, 2H), 2.90 (m, 1H), 2.58 (m, overlaid with DMSO, 1H), 2.32 (m, 1H), 2.09-1.90 (m, 2H), 1.67-1.53 (m, 2H), 1.09 (m, 1H); HR ESI-MS (M+H)+ m/z = 516.1719 (calc. for C24H27N5O5FS: 516.1717) ; tR = 1.12.
6-((((3R,6S)-6-((1R,2R)-2-(8-fluoro-6-methoxyquinolin-4-yl)-1,2dihydroxyethyl)tetrahydro-2H-pyran-3-yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin3(4H)-one (50c). The compound 50c was obtained in 39% yield from 50b and 32 and using the general procedure B. Yellowish solid; 1H NMR (CDCl3) δ: 10.85 (s, 1H), 8.76 (d, J = 4.4 Hz, 1H), 7.73 (d, J = 7.8 Hz, 1H), 7.64 (d, J = 4.5 Hz, 1H), 7.32 (dd, J = 2.4, 11.9 Hz, 1H), 7.28 (d, J = 2.6 Hz, 1H), 7.07 (d, J = 7.9 Hz, 1H), 5.46 (d, J = 5.5 Hz, 1H), 5.33 (t, J = 4.9 Hz, 1H), 5.17 (d, J = 5.8 Hz, 1H), 3.92 (overlaid m, 1H), 3.89 (s, 3H), 3.72 (d, J = 3.9 Hz, 2H), 3.53 (overlaid m, 1H), 3.52 (s, 2H), 2.96 (m, 1H), 2.74 (t, J = 10.4 Hz, 1H), 2.52 (m, overlaid with DMSO, 2H), 2.03 (m, 1H), 1.59 (m,
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Journal of Medicinal Chemistry
2H), 1.05 (m, 1H); HR ESI-MS (M+H)+ m/z = 515.1769 (calc. for C25H28N4O5FS: 515.1764) ; tR = 1.06.
6-((((3R,6S)-6-((1S,2R)-1,2-dihydroxy-2-(6-methoxyquinolin-4-yl)ethyl)tetrahydro2H-pyran-3-yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin-3(4H)-one
(51c).
The
compound 51c was prepared in 21% yield from 51b and 32 and using the general procedure B. White solid 1H NMR (DMSO) δ: 10.87 (s, 1H), 8.71 (d, J = 4.5 Hz, 1H), 7.93 (d, J = 9.1 Hz, 1H), 7.73 (d, J = 7.9 Hz, 1H), 7.54 (d, J = 4.5 Hz, 1H), 7.44 (d, J = 2.6 Hz, 1H), 7.40 (dd, J = 2.6, 9.1 Hz, 1H), 7.07 (d, J = 7.9 Hz, 1H), 5.41 (d, J = 5.2 Hz, 1H), 5.35 (t, J = 5.2 Hz, 1H), 4.79 (d, J = 6.4 Hz, 1H), 3.94 (m, 1H), 3.88 (s, 3H), 3.72 (br. d, J = 4.0 Hz, 1H), 3.53 (s, 2H), 2.92 (m, 1H), 2.71 (t, J = 10.8 Hz, 1H), 2.01 (m, 1H), 1.63 (m, 2H), 1.23 (m, 1H), 1.06 (m, 1H); HR ESI-MS (M+H)+ m/z =497.1852 (calc. for C25H29N4O5S: 497.1858) ; tR = 0.80.
6-((((3R,6S)-6-((1S,2R)-1,2-dihydroxy-2-(3-methoxyquinoxalin-5-yl)ethyl)tetrahydro2H-pyran-3-yl)amino)methyl)-2H-pyrido[3,2-b][1,4]thiazin-3(4H)-one
(52c).
The
compound 52c was prepared in 39% yield from 52b and 32 according to the general procedure B. Yellowish foam 1H NMR δ (DMSO-d6): 10.84 (s, 1H), 8.57 (s, 1H), 7.80-7.89 (m, 2H), 7.71 (d, J = 7.7 Hz, 1H), 7.60 (app t, J = 7.7 Hz, 1H), 7.06 (d, J = 7.9 Hz, 1H), 5.64 (m, 1H), 5.07 (d, J = 6.3 Hz, 1H) 4.25 (d, J = 6.3 Hz, 1H), 3.99 (overlaid m, 1H), 3.98 (s, 3H), 3.91 (m, 1H), 3.66-3.76 (m, 2H), 3.58 (m, 1H), 3.50 (s, 2H), 3.25 (overlaid m, 1H), 2.83 (t, J = 10.6 Hz, 1H), 2.50 (overlaid m, 1H), 2.10 (br s, 1H), 2.05 (m, 1H), 1.86 (m, 1H), 1.47 (m, 1H), 1.19 (m, 1H); HR ESI-MS (M+H)+ m/z = 498.1814 (calc. for C24H28N5O5S: 498.1811); tR = 1.15.
General procedure E: Reductive amination reaction using aldehydes 33, 53-55. To a solution of amine (1eq.) in MeOH (5 mL/mmol) was added the appropriate aldehyde (1eq.). The reaction mixture was stirred at rt overnight. The reaction mixture was cooled to 0 °C and NaBH4 (400 mol%) was added. After stirring for 40 min, DCM-MeOH (9-1, 6 mL/mmol) and saturated NaHCO3 (2 mL/mmol) were added. The two layers were decanted and the aq layer was extracted with a DCM-MeOH mixture (9-1, 4 x 5 mL/mmol). The combined organic layers were washed with brine,
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dried over Na2SO4, filtered and concentrated to dryness. The residue was purified by chromatgraphy (DCM-MeOH containing aq NH4OH) to afford the corresponding alkylated product.
(1S,2R)-1-((2S,5R)-5-(((2,3-dihydro-[1,4]dioxino[2,3-c]pyridin-7yl)methyl)amino)tetrahydro-2H-pyran-2-yl)-2-(6-fluoro-3-methoxyquinoxalin-5yl)ethane-1,2-diol (48d). Starting from of 48b (0.08 g, 0.23 mmol) and 33 (0.042 g, 0.25 mmol), 48d (0.068 g, 59%) was prepared using the general procedure E. Off-white solid; 1H NMR δ (DMSOd6): 8.54 (s, 1H), 7.95 (dd, J = 5.5, 10.3 Hz, 1H)), 7.95 (s, 1H), 7.46 (dd, J = 9.3, 10.3 Hz, 1H), 6.83 (s, 1H), 5.64 (t, J = 6.9 Hz, 1H), 5.1 (d, J = 6.8 Hz, 1H), 4.68 (d, J = 6.0 Hz. 1H), 4.29-4.33 (m, 2H), 4.23-4.27 (m,2H), 4.02 (s, 3H), 3.90 (m, 1H), 3.69 (m, 1H), 3.50-3.60 (m, 2H), 2.76 (m, 1H), 2.42 (t, J = 10.6 Hz, 1H), 2.27 (m, 1H), 1.83-1.98 (m, 2H), 1.40-1.63 (m, 2H), 0.97 (m, 1H); HR ESI-MS (M+H)+ m/z = 487.1996 (calc. for C24H28N4O6F: 487.1992); tR = 1.11.
(1S,2R)-1-((2S,5R)-5-(((2,3-dihydro-[1,4]oxathiino[2,3-c]pyridin-7yl)methyl)amino)tetrahydro-2H-pyran-2-yl)-2-(6-fluoro-3-methoxyquinoxalin-5yl)ethane-1,2-diol (48e). Starting from of 48b (0.099 g, 0.29 mmol) and 53 (0.054 g, 0.29 mmol), 48e (0.079 g, 54%) was prepared using the general procedure E; Off-white foam; 1H NMR δ (DMSOd6): 8.55 (s, 1H), 7.95 (dd, J = 5.5, 10.3 Hz, 1H)), 7.89 (s, 1H), 7.46 (dd, J = 9.3, 10.3 Hz, 1H), 6.83 (s, 1H), 5.65 (t, J = 6.9 Hz, 1H), 5.1 (d, J = 6.8 Hz, 1H), 4.68 (d, J = 6.0 Hz. 1H), 4.32-4.37 (m, 2H), 4.01 (s, 3H), 3.90 (m, 1H), 3.69 (m, 1H), 3.49-3.60 (m, 2H), 3.20-3.24 (m, 2H), 2.76 (m, 1H), 2.42 (t, J = 10.6 Hz, 1H), 2.27 (m, 1H), 1.82-1.95 (m, 2H), 1.41-1.65 (m, 2H), 0.96 (m, 1H); HR ESI-MS (M+H)+ m/z = 503.1767 (calc. for C24H28N4O5FS: 503.1764); tR = 1.22.
(1S,2R)-1-((2S,5R)-5-(((6,7-dihydro-[1,4]oxathiino[2,3-c]pyridazin-3yl)methyl)amino)tetrahydro-2H-pyran-2-yl)-2-(6-fluoro-3-methoxyquinoxalin-5yl)ethane-1,2-diol (48f). Starting from of 48b (0.070 g, 0.20 mmol) and 55 (0.038 g, 0.29 mmol), 48f (0.070 g, 67%) was prepared using the general procedure E. Off-white; 1H NMR δ (DMSO-d6): 8.55 (s, 1H), 7.95 (dd, J = 5.5, 10.3 Hz, 1H)), 7.46 (dd, J = 9.3, 10.3 Hz, 1H), 7.45 (s, 1H), 5.65 (t, J = 6.9 Hz, 1H), 5.1 (d, J = 6.8 Hz, 1H), 4.68 (d, J = 6.0 Hz. 1H), 4.53-4.58 (m, 2H), 4.01 (s, 3H), 3.90 (m,
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1H), 3.65-3.74 (m, 3H), 3.24-3.30 (m, 2H), 2.75 (m, 1H), 2.41 (t, J = 10.6 Hz, 1H), 2.27 (m, 1H), 2.09 (m, 1H), 1.88 (m, 1H), 1.54 (m, 1H), 1.46 (m, 1H), 0.96 (m, 1H); HR ESI-MS (M+H)+ m/z = 504.1713 (calc. for C23H27N5O5FS: 504.1717); tR = 1.01.
(1S,2R)-1-((2S,5R)-5-(((2,3-dihydro-[1,4]dioxino[2,3-c]pyridin-7yl)methyl)amino)tetrahydro-2H-pyran-2-yl)-2-(3-fluoro-6-methoxy-1,5-naphthyridin-4yl)ethane-1,2-diol (49d). Starting from of 49b (1.5 g, 4.45 mmol) and 33 (0. 74 g, 4.47 mmol), 49d (0.85 g, 39%) was obtained using the general procedure E. White solid; 1H NMR δ (DMSO-d6): 8.72 (d, J = 1.8 Hz, 1 H), 8.26 (d, J = 9.1 Hz, 1 H), 7.96 (s, 1 H), 7.20 (d, J = 9.1 Hz, 1 H), 6.85 (s, 1 H), 5.68 (t, J = 6.6 Hz, 1 H), 5.41 (d, J = 7.1 Hz, 1 H), 4.79 (d, J = 6.1 Hz, 1 H), 4.30-4.34 (m, 2H), 4.214.26 (m, 2H), 3.98 (s, 3H), 3.85 (m, 1H), 3.70 (m, 1H), 3.52-3.62 (m, 2H), 2.94 (m, 1H), 2.54 (t, J = 10.6 Hz, 1H), 2.27 (m, 1H), 2.10 (br s, 1H), 1.91 (m, 1H), 1.49-1.61 (m, 2H), 1.03 (m, 1H); HR ESIMS (M+H)+ m/z = 487.1990 (calc. for C24H28N4O6F: 487.1993) ; tR = 1.11.
(1S,2R)-1-((2S,5R)-5-(((2,3-dihydro-[1,4]oxathiino[2,3-c]pyridin-7yl)methyl)amino)tetrahydro-2H-pyran-2-yl)-2-(3-fluoro-6-methoxy-1,5-naphthyridin-4yl)ethane-1,2-diol (49e). Starting from of 49b (1.9 g, 5.63 mmol) and 53 (0.036 g, 0.23 mmol), 49e (1.5 g, 53%) was prepared using the general procedure E. White solid; m.p.= 133.1 °C; 1H NMR δ (DMSO-d6): 8.72 (d, J = 1.8 Hz, 1 H), 8.26 (d, J = 9.1 Hz, 1 H), 7.89 (s, 1 H), 7.21 (d, J = 9.1 Hz, 1 H), 7.07 (s, 1 H), 5.68 (t, J = 6.6 Hz, 1 H), 5.41 (d, J = 7.1 Hz, 1 H), 4.78 (d, J = 6.1 Hz, 1 H),4.314.37 (m, 2H), 3.98 (s, 3H), 3.85 (m, 1H), 3.71 (m, 1H), 3.50-3.63 (m, 2H), 3.20-3.25 (m, 2H), 2.94 (m, 1H), 2.53 (t, J = 10.5 Hz, 1H), 2.26 (m, 1H), 1.85-1.96 (m, 2H), 1.47-1.63 (m, 2H), 1.03 (m, 1H); 13C NMR δ (CDCl3): 162.0, 155.0 (d, J = 270 Hz), 151.5, 147.4, 141.2 (d, J = 6 Hz), 141.1, 139.2, 138.7, 138.6 (d, J = 28 Hz), 129.2, 128.3 (d, J = 11 Hz), 119.9, 115.7 (d, J = 2Hz), 85.8, 72.6, 69.3 (2C), 64.8, 54.3, 53.0, 51.8, 30.7, 26.8, 25.7; HR ESI-MS (M+H)+ m/z = 503.1765 (calc. for C24H28N4O5FS: 503.1764); tR = 0.81.
(1S,2R)-1-((2S,5R)-5-(((6,7-dihydro-[1,4]oxathiino[2,3-c]pyridazin-3yl)methyl)amino)tetrahydro-2H-pyran-2-yl)-2-(3-fluoro-6-methoxy-1,5-naphthyridin-4-
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yl)ethane-1,2-diol (49f). Starting from of 49b (0.105 g, 0.31 mmol) and 55 (0.060 g, 0.33 mmol), 46f (0.090 g, 57%) using the general procedure E. Off-white foam; 1H NMR δ (DMSO-d6): 8.73 (d, J = 1.6 Hz, 1 H), 8.26 (d, J = 9.0 Hz, 1 H), 7.47 (s, 1 H), 7.21 (d, J = 9.1 Hz, 1 H), 5.68 (t, J = 6.6 Hz, 1 H), 5.41 (d, J = 7.0 Hz, 1 H), 4.79 (d, J = 6.1 Hz, 1 H), 4.52-4.59 (m, 2H), 3.98 (s, 3H), 3.85 (m, 1H), 3.66-3.72 (m, 3H), 3.24-3.31 (m, 2H), 2.93 (m, 1H), 2.53 (t, J = 10.5 Hz, 1H), 2.26 (m, 1H), 1.85-1.96 (m, 2H), 1.46-1.62 (m, 2H), 1.02 (m, 1H); HR ESI-MS (M+H)+ m/z = 504.1714 (calc. for C23H27N5O5FS: 504.1717); tR = 0.69.
(1S,2R)-1-((2S,5R)-5-(((6,7-dihydro-[1,4]dioxino[2,3-c]pyridazin-3yl)methyl)amino)tetrahydro-2H-pyran-2-yl)-2-(3-fluoro-6-methoxy-1,5-naphthyridin-4yl)ethane-1,2-diol (49g). Starting from of 49b (0.071 g, 0.21 mmol) and 54 (0.036 g, 0.23 mmol), 49g (0.038 g, 37%) was prepared using the general procedure E. Off-white foam; 1H NMR δ (DMSOd6): 8.74 (d, J = 1.7 Hz, 1 H), 8.27 (d, J = 9.1 Hz, 1 H), 7.22 (d, J = 9.1 Hz, 1 H), 7.11 (s, 1 H), 5.68 (t, J = 6.5 Hz, 1 H), 5.43 (d, J = 7.1 Hz, 1 H), 4.81 (d, J = 6.1 Hz, 1 H), 4.46-4.51 (m, 2H), 4.34-4.41 (m, 2H), 3.98 (s, 3H), 3.68-3.79 (m, 3H), 2.94 (m, 1H), 2.54 (t, J = 10.6 Hz, 1H), 2.26 (m, 1H), 2.16 (br s, 1H), 1.91 (m, 1H), 1.51-1.62 (m, 2H), 1.05 (m, 1H); HR ESI-MS (M+H)+ m/z = 488.1948 (calc. for C23H27N5O6F: 488.1945); tR = 0.95. AUTHOR INFORMATION Corresponding Author *Phone: +41 61 565 65 65. Fax: + 41 61 565 65 00. E-mail:
[email protected]. +
retired on 2012, December 31st.
Notes The authors declare no competing financial interest.
ACKNOWLEDGMENTS We gratefully acknowledge our colleagues from Process Research, Drs Stefan Abele, Jacques-Alexis Funel and their coworkers Stéphanie Combes and Ivan Schindelholz for the excellent support they provided. Samantha Saxer and François Le Goff are warmly thanked for the technical support they provided during the preparation of the manuscript.
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ABBREVIATIONS USED NBTI, novel (non-fluoroquinolone) bacterial type II topoisomerase inhibitor; QR, quinolone-resistant; LHS, bicyclic aromatic left-hand side; RHS, aromatic right-hand side (as positioned in Figure 2); NHS, N-hydroxysuccinimide; CSA, (+/-)-10-camphorsulfonic acid; CFU, colony forming unit, RIA, Relaxation Inhibitory Activity; SCIA, Supercoling Inhibitory Activity; Et2O, diethyl ether; EtOAc, ethyl acetate; PT-SH, phenyl tetrazole thiol; t-BuOH, tert-butanol (2-methyl-2-propanol); t-BuOK, potassium tert-butoxide. ASSOCIATED CONTENT * Supporting Information Experimental details on synthesis and characterization of the aldehydes 19b-27b. Representative gels for SCIA and RIA assays. Table containing the comparative data of 49e with Ciprofloxacin and Linezolid. This material is available free of charge via the Internet at http://pubs.acs.organic Accession Code The RCSB PDB code for the co-crystal structure of compound 4 with S. aureus GyrB27-A56 used for modeling is 2XCS22.
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(50) Comparative data of 49e with Ciprofloxacin and Linezolid are provided in Supporting Information. (51) Giuliano, C.; Jairaj, M.; Zafiu, C.M.; Laufer, R. Direct determination of unbound intrinsic drug clearance in the microsomal stability assay. Drug Metab. Dispos. 2005, 33, 1319-1324. (52) Andes, D.; Craig, W. A. Animal model pharmacokinetics and pharmacodynamics: a critical review. Int. J. Antimicrob. Agents 2002, 19, 261-268. (53) Kutchinsky J.; Friis, S.; Asmild, M.; Taboryski, R.; Pedersen, S.; Vestergaard, R. K.; Jacobsen, R.B.; Krzywkowski, K.; Schroder, R. L.; Ljungstrom, T.; Helix, N.; Sorensen, C. B.; Bech, M.; Willumsen, N. J. Characterization of potassium channel modulators with QPatch automated patchclamp technology: system characteristics and performance. Assay Drug Dev. Technol. 2003, 1, 685693.
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